Thanks to an unholy tangle of technical issues and legal injunctions, it has taken 47 years for the concert film Amazing Grace to reach the screen. Few will deny, however, that the wait has been worthwhile, as this is a thrilling vérité record of Aretha Franklin's two-night sojourn at the New Temple Missionary Baptist Church in the Watts district of Los Angeles in January 1972. 

Having started singing gospel music at the age of 14 in her pastor father CL Franklin's Detroit church, Franklin felt the need to return to her roots, as she approached her 30th year. By all accounts, her record label was reluctant to let her make a gospel album, as the suits feared the tracks would get little airplay on cross-over radio stations and that the kids who had bought Franklin's 20 LPs and 11 chart-topping singles would be put off by a dose of old-time religion.   

But Franklin insisted on staging the concert under the musical direction of the Reverend James Cleveland and word reached the front office of Warner Brothers, who sent director Sydney Pollack and a film crew to capture the event for posterity, as concert movies had acquired a certain cachet. In an effort not to disturb Franklin and her fellow performers, however, Pollack decided not to use clapperboards during the shoot, with the result that he was left with several cans of unsynchronised sound and imagery. When it came to edit the material, therefore, it was impossible to achieve an audiovisual match up and, even though the soundtrack album went on to become the biggest-selling release of Franklin's career, the decision was taken to abandon the accompanying documentary.

In 2007, music executive Alan Elliott mortgaged his house to buy the reels that had been gathering dust in the Warner vault. The dying Pollack gave him his blessing and, with the likes of Spike Lee joining the roster of producers, Elliott used the latest digital equipment to lock sound and vision together. Modestly, he only takes a simple `realised by' credit on a picture that would have knocked Blaxploitation back on its heels back in the early 70s. Yet, even though the print was ready to release in 2015, Franklin refused to give her permission for it to be shown, even on the festival circuit. Thus, it is only with her passing on 16 August last year that Elliott has finally been able to present one of the rough-and-ready gems of rockumentary cinema. 

Resplendent in the silver spangled waistcoats worn over their simple black robes, the members of the Southern California Community Choir proclaim they are on the road to glory, as they are led into the church by the Reverend Cleveland. As they take their seats behind the pulpit, the `King of Gospel Music' reminds the sparse congregation that they are about to witness a live recording and that there might be the occasional need to do things again. He also urges them to sound like 2000 to create a vibrant atmosphere. 

Wearing a plain white kaftan and ornate drop earrings, Aretha Franklin walks sedately down a side aisle and takes her place at the piano to open with the Marvin Gaye number, `Wholy Holy'. She is clearly in fine voice and has come to give praise rather than play the soul diva. Indeed, she allows Cleveland to do all of the talking between the numbers and mostly listens demurely, with her eyes lowered and her thoughts focused. 

Cleveland reminds the assembled that Franklin in a preacher's daughter, as he takes over at the piano for `What a Friend We Have in Jesus'. In an effort to provide a little variation, editor Jeff Buchanan starts `How I Got Over' with a rehearsal clip before cutting back to the concert, as Franklin's face becomes beaded with perspiration, as she belts out the lyrics. 

She duets with Cleveland on `Precious Memories', during which he calls on the congregation to raise a hand to show their love for the Lord. He also encourages everyone to shake hands with the person next to them and tell them about their faith in Jesus Christ. It's heady stuff and Franklin raises her hand along with everyone else before greeting conductor, Alexander Hamilton.

The excellence of his choir is very much in evidence in the medley composed of `Precious Lord, Take My Hand and a rejigging of Carole King's `You've Got a Friend' that manages to be both deeply spiritual and musically exhilarating. However, Franklin saves the best for last. After Cleveland reveals that she had tears in her eyes during rehearsals, she produces a truly magnificent rendition of `Amazing Grace' that has the choristers jumping up and shouting their encouragement during a performance of power and poignancy. 

At one point, Cleveland has to step away from the piano to cover his face with a cloth and Hamilton slips seamlessly into his place. But the preacher regains his composure in time to whisk Franklin away from the pulpit while promising the congregation that the second night will be even more remarkable. Strains of George Harrison's `My Sweet Lord' can be heard in the recessional jam played by guitarist Cornell Dupree, bassist Chuck Rainey, organist Kenny Luper, drummer Bernard Purdie and percussionist Poncho Morales, as Franklin departs and the image fades. 

Throughout the first half, Sydney Pollack and his crew have been discreetly visible, while scuttling around the tiny dais to get the best shots of Franklin, Cleveland, the animated choir and the awestruck audience. Scene-setting shots provide a bridge into the second night, which is made a little more stellar by the presence of Rolling Stones Mick Jagger and Charlie Watts, who had taken a break from the Exile on Main Street sessions to sit at the back of the church and marvel at Franklin's brilliance.

Taking the microphone, Cleveland asks how many people have returned for a second night, as word has clearly got round because the congregation has almost doubled in size. They applaud enthusiastically, as Aretha enters wearing a green-patterned kaftan and a chunky gold chain. At various points, she will sport a pair of earrings, but (as in a continuity assistant's nightmare), they come and go as the evening progresses. Once again, she remains modestly detached, as she leaves the talking to Cleveland and concentrates on the task at hand. 

She opens with the spiritual `Mary, Don't You Weep' before Cleveland welcomes fur-bedecked gospel legend Clara Ward to the front pew, along with Aretha's preacher father, Clarence Franklin, who glad hands his way along the aisle in a natty blue suit. His presence seems to unsettle his daughter, who false starts on `Climbing Higher Mountains', which Cleveland dedicates to her father.

Unable to resist, the camera picks out Jagger, as he gets to his feet to clap and sway along to the rocking reprise. The screen splits briefly to show Aretha and Cleveland duetting before what appears to be a mother and daughter come to the front to contribute an impromptu buck-and-wing dance routine. A choir member with a passing resemblance to James Brown also struts his stuff in urging Aretha on, as she improvises at the pulpit. She also claps along vigorously to `Old Landmark', a rousing foot-stomper that once again showcases the excellence of the choir. 

By now, Jagger has edged his way towards the front and he is seen in close-up, as Cleveland asks CL Franklin to say a few words. Aretha smiles quietly, as he praises the choir and the band. But she looks a bit embarrassed, as her father recalls hearing her sing at home when she was six years old. She joined him on the road at 11 and helped people praise the Lord with her voice. Franklin acknowledges the influence of Clara Ward and Mahalia Jackson on Aretha's style and thanks Cleveland for his contribution to fostering her talent. In conclusion, Franklin remembers being asked in a dry cleaner's when Aretha was going to come back to the church and he insists that she has never left it. 

The homily sits a little awkwardly in proceedings and those aware of the subsequent revelations about Franklin's private life will doubtless read much into Aretha's body language. Opinion will also be divided about the way in which Franklin comes forward to mop his daughter's brow, as she sits at the piano for `Never Grow Old', before returning to his seat to exchange wisecracks with his assistant. The sense that the guests are striving to draw focus away from Aretha is confirmed when Pollack scrambles past her to get shots of Clara Ward dancing with her elderly mother. 

Aretha closes her eyes to shut out the distractions on the front row, as she completes the song. But she throws herself into the reprise, as she joins the choir in rousing repetitions of the line `so glad I got religion' that has every single soul on their feet. As the applause dies down, Aretha expresses her thanks before wishing God's blessing on everyone and the night draws to a close. 

With the rawness of the footage adding to `being there' intimacy of Pollacks's shooting style, this is a priceless record of a landmark performance. Backed by the larger-than-life Cleveland, a fine band (drawn from the Atlantic Records session ranks) and an extraordinary choir, Franklin delivers the gospel standards that evidently mean a good deal to her with the sincerity and artistry that set her apart from her contemporaries on the soul, funk and R&B scenes. The personal nature of the project shines through, as Franklin performs for a celestial, as much as for a temporal audience. But there's nothing pompously pious about her set, as she sings to please, as well as preach and praise. 

Sadly, the aggregated delays mean that the documentary won't have the socio-cultural impact that it might well have had in 1972. But any hip-hop fan with a knowledge of musical history will recognise the significance of gospel in the evolution of African-American music and will treasure this as a seminal moment in the career of Aretha Franklin and in the development of black community consciousness in the aftermath of the Civil Rights campaign and the emergence of the Black Panthers. After Tuesday's miracle at Anfield, however, it's a shame there was no room for Aretha's version of `You'll Never Walk Alone', which can be found on the soundtrack album.

If a documentary on a sensationalist subject is going to engross and convince, it requires more than just a good story. It needs to be told from an objective viewpoint and reach a credible conclusion, otherwise its content will merely have curiosity value and it will run the risk of becoming nothing more than a `stranger than fiction' anecdote. British debutant Tim Wardle couldn't have a more compelling topic in Three Identical Strangers. But, in seeking to apportion blame for the travesties and tragedies it unearths, this well-intentioned exposé stumbles into conspiracy territory without possessing the necessary evidence to conclusively prove its contentions.

Sitting down in front of the camera, Bobby Shafran admits that his story seems far-fetched. But he can vouch for every word of it being true, as he takes us back to 1980, when the 19 year-old Bobby drove a battered Volvo nicknamed `The Old Bitch' to in the Catskills in order start his first term at Sullivan County Community College. He was surprised that so many people kept greeting him like a long-lost friend and it was only when someone called him `Eddy' that he had pause for thought. 

Michael Domnitz had been Eddy's best pal and he had burst into his dorm room to ask Bobby if he had a twin. When he replied in the negative, Domnitz had inquired about his birthday and they quickly established that Bobby and Eddy Galland were both born on 12 July 1961. Intrigued, the pair had dashed to a call box to phone Eddy. Following a brief conversation, during which the strangers learn they were both adopted from the Louise Wise Services agency, Eddy and Domnitz drove to Long Island and got a speeding ticket in their haste to solve the mystery. When they eventually arrived, Eddy was amazed to be confronted with his double and they realised  immediately that they were identical twins. 

When Howard Schneider at Newsday got a call about the story, he initially thought it was a hoax. But he soon recognised it was a major scoop and it was picked up by other outlets, including the New York Post. This is where Ellen Cervone and Alan Luchs spotted Bobby and Eddy's resemblance to their friend, David Kellman, and his mother confirmed that he had also been born on the same day at Long Island Jewish Hospital. David had called Eddy's home and spoken to his astonished mother and arranged a reunion at the home of his aunt, Hedy Page, who remembers them romping around like puppies within minutes of being reunited. 

Bobby's parents, Mort and Alice Shafran, and Eddy's father, Elliott Galland, also recall their surprise and joy at seeing the boys together. We see old home movies of them walking with their arms around each other and playing frisbee in the street. They also compared notes on their lives so far and David was pleased that he had a better car than Bobby, when his adoptive father was an eminent Scarsdale physician. 

Amidst the euphoria, Eddy wondered whether their meeting was going to be a good or a bad thing. But they had little time to contemplate the complexities of their situation, as they were whisked off to become overnight media celebrities. They appeared on chat shows and magazine covers across the nation and, in the clips with Phil Donahue and Tim Brokaw, their expressions and mannerisms are eerily similar. Everything seemed wondrous and fun, as they also discovered that they had the same tastes in food, cigarettes and (older) women. Moreover, they realised that they each had an adopted sister who was two years their senior.

Yet, while they forged an instant bond, they were still essentially strangers from very different backgrounds. Bobby had been raised by a doctor and a lawyer, while Eddy's father was a teacher from a middle-class suburban home. By contrast, David had been raised by blue-collar immigrant parents, who owned a small shop and spoke English as a second language. But the triplets preferred sharing their together time with Richard Kellman, who was nicknamed `Bubala' and was delighted to be able to declare Bobby and Eddy his new sons. 

However, Aunt Hedy recalls the anger of the adoptive parents at not being told that their child had brothers. She also reflects on how scary it must have been for six-month infants to suddenly find themselves alone after sharing a crib with two others. Indeed, both Bobby and David used to bang their heads against the bars of their cots in what they have since been informed were manifestations of separation anxiety. 

As the novelty of the reunion subsided, questions started to be asked about the role of Louise Wise Services, which had enjoyed an impeccable reputation since its founding in 1916. Speaking in 1982, company president Justine Wise Polier had insisted that it would have been better to have kept the siblings together. However, when the senior LWS team first met with the furious families, they had revealed that the brothers were parted because it would have been impossible to find anyone who would have taken all three. This feeble excuse infuriated Richard Kellman, who would willingly have adopted the triplets. But it was Mort Shafran who had made the most sinister discovery of the evening, as he had returned to retrieve a forgotten umbrella and seen the agency hierarchy opening a bottle of champagne with a gusto that suggested they thought they had dodged a bullet. 

None of this bothered the boys at the time, however, who were too busy living it large in New York and being papped at Studio 54, Limelight and the Copacabana. They even made a cameo appearance ogling Madonna in Susan Seidelman's Desperately Seeking Susan (1985) before getting an apartment together. As Luchs and Cervone recall, they partied hard and Bobby and David admit to having had a ball. During this period, they also found their future wives and Ilene Shafran, Janet Kellman and Brenda Galland all insist that they got the pick of the litter. 

Everyone agrees that Eddy got the biggest kick out of the reunion and it was he who proposed that they should try to track down their birth mother. After going through the records at the New York Public Library, they found her address and arranged a meeting at her local bar. During the course of the evening, she had explained that she had been very young when she got pregnant. But, while they sympathised with her plight at having become pregnant on her prom night, none of the boys felt a particularly strong connection. 

David remembers being disturbed by how much she booze she had guzzled in such a short space of time and concedes that she only played a minor role in their story. This had taken another turn, however, as the brothers had opened the Triplets restaurant in SoHo. Footage shows the trio orchestrating the fun and David reveals that they cleared $1 million in their first year, as busloads of curiosity seekers came to be waited on by the lookalikes. 

As Cervone reveals, however, it was also around this time that things started to go `a little funky'. Journalist Lawrence Wright was researching an article for the New Yorker on separated twins when he came across an article in a journal entitled The Psychoanalytic Study of the Child, which claimed that siblings had been selected from Louise Wise Services and placed in different home. Realising that this had been a conscious policy, Wright had contacted the triplets, who were appalled by the news. 

However, they all recalled being subjected to regular aptitude tests throughout their childhoods by a couple who would film their responses with a 16mm camera. As the families had been told that this was part of a survey of adopted children born within a specific time frame, they had thought nothing of it. But the realisation that scientists had been systematically visiting the brothers over many years, while fully aware that they lived within a 100-mile radius of each other, proved deeply disturbing. 

Wright also discovered that the person leading the inquiry was Dr Peter Neubauer, an Austrian refugee from the Holocaust, who was not only one of the most pre-eminent psychiatrists in New York, but who was also in charge of the Sigmund Freud archive. Among the twins Neubauer studied were Paula Bernstein and Elyse Schein, who turned out to be film school graduates and went on to co-author the book, Identical Strangers. But Wright couldn't figure out what Neubauer had been striving to achieve, as he had never published his study and had imposed stringent legal restrictions that prevented anyone who had been under his scrutiny from accessing the paperwork. 

Undaunted, Wardle tracks down Natasha Josefowitz, who had been Neubauer's research assistant at the Child Development Centre. She now lives in La Jolla, California and shows the crew around her comfortable home, pausing to show off photographs of her posing with Errol Flynn, Robert Reford, Al Gore and Barack and Michelle Obama. But Josefowitz is more than willing to discuss Neubauer and his study, although she insists that she was on its periphery rather than an active participant. Nevertheless, she heard it being discussed in the office and still believes that its aim to discern whether humans are the product of `nature or nurture' was worthwhile. 

Josefowitz also asserts that the study took place in very different times to our own, when the cause of scientific discovery was paramount and few had serious scruples about deliberately separating unwanted twins at birth and charting their development in isolation. However, as she had relocated to Switzerland in 1965, she had lost touch with Neubauer and has no idea what happened to his findings. Nevertheless, knowing his intellect, she has little doubt that they would have been momentous. 

Aunt Hedy explains that Holocaust survivors know all about the damage that cruel experimentation can cause and she remembers thinking that the triplets were throwing themselves into their relationship without having had the benefit of coming to understand each other as individuals while growing up in a shared space. Thus, when Richard Kellman died and the siblings started arguing about workloads and responsibilities at Triplets, Bobby decided to back out and Eddy and David felt betrayed. Speaking to camera, both David and Bobby agree that this breach damaged the bond beyond repair and they concede that things between them were never quite the same again. 

As he had been the keenest to make the reunion work, Eddy was hit the hardest when the road got rocky. Brenda recalls how his behaviour had become increasingly erratic, while his moods had started to swing. Eventually, Eddy was diagnosed with manic depression and committed to a psychiatric facility and David particularly emphathised with him because he had been hospitalised during his teens. Indeed, all three siblings had experienced problems in adolescence, with Bobby being caught up in a murder case when he had covered for some friends. 

Yet the adoptive parents had seemingly never been informed about any incidence of mental illness in the birth family. By contrast, Elyse Schein had received a letter from Louise Wise Services explaining that her birth mother had been diagnosed with schizophrenia and had spent many years in therapy and/or institutions. When David is asked if their own mother had had mental health problems, he speculates that she might have had some minor difficulties. But he doesn't know for sure and looks uneasily into the camera. 

Bobby similarly shifts in his seat when asked about Eddy and he suggests that Wardle lets David fill in the details. He recalls Eddy failing to turn up for front of house duties at the restaurant and, as they lived opposite each other, he had called Janet to see if his brother's car was in the drive. She had gone to check on Eddy and had called David back in great distress and had pleaded with him to come home. By the time he arrived, however, the police had sealed off the house and David was informed that he wouldn't want to see what had happened inside. 

With the pain still evident, Bobby explains that Eddy had shot himself and he appears to go into a daze, as he stares into the lens reliving his emotions when David had called him. He had sensed something was wrong before his brother had spoken to him and David similarly drifts off into his own thoughts before the camera prior to wandering off the set in a state of numbness. 

Having discovered that the majority of the separated twins and triplets in Neubauer's study were born to mothers with a history of mental illness, Wright concluded that he had been seeking to determine whether such conditions were heritable. After Eddy's death in 1995, David vowed to find out what was in the study, in case it had any ramifications for himself and his family down the line. However, when Neubauer died in 2008, he donated his archive to Yale and placed it under embargo until 2066. When David calls the Jewish Board of Family and Children's Services to see if it would be willing to let him see the material, he is repeatedly fobbed off and Wright reveals that this body has some very powerful backers who would not want to incur any resulting adverse publicity if the documents proved combustible. 

Wright had interviewed Neubauer on tape and his evasive responses to questions about a possible publication date suggest that he had no intention of going public with his findings. But Wardle tracks down his former assistant, Lawrence Perlman, to Ann Arbor, Michigan and he is willing to discuss his part in the study. For 10 months, the 24 year-old Perlman had been one of the field assessors who had visited the homes of Neubauer's twins and triplets and he jokes that he was always aware that he couldn't let slip casual remarks about having recently seen their siblings, as he would have given the entire game away. He also reads from some notes he had taken during his visits to Bobby, Eddy and David and insists that he was solely studying the parental style of the different families and reveals that the older sisters had already been placed with them in order to provide some points of comparison. 

David and Bobby come together on camera to view Perlman's interview on a laptop and they agree to feeling like lab rats. Alice Shafran explains that the families were very different, with Richard Kellman doting on David's every deed, while her husband, Mort, had been a busy man and didn't always have sufficient free time to spend with him. However, she insists that Mort was equally devoted in suggesting that Eddy had the toughest relationship with his father because Elliott Galland was a traditional disciplinarian, whose word was law. 

Aunt Hedy posits that Eddy had a tough time and recalls that he didn't talk about Elliott, who rarely attended family gatherings. Brenda concurs that they were very different, as Eddy was arty and his father had a very soldierly approach to life. Elliott admits that he could be strict and Brenda says Eddy often confided in her that he was an outsider who felt he was in the wrong place. Elliott admits that he didn't preside over a sharing family when it came to problems. But he maintains that they had looked out for one another at all times and neither Bobby nor David blames him for what happened to their brother. Eddy simply didn't fit in and this happens in biological families, too. Nevertheless, Elliott clearly regrets not helping his son prepare for life's vicissitudes and reveals that he and his wife had sobbed when they had been told that Eddy had committed suicide. 

Concluding captions reveal that the Jewish Board of Family and Children's Services had responded to new of the making of the film by giving David and Bobby access to 10,000 pages from the Neubauer files. The majority, however, had been heavily redacted and, even if Neubauer had reached any definitive conclusions, they had been withheld. As the film ends, Perlman and Josefowitz confess that four individuals from the study remain unaware that they have a twin. David finds this mind-boggling, although Wright implies that no one should be surprised if they turned a corner and bumped into a twin whose existence had been suppressed in the name of scientific research. 

This final declaration rather sums up the problem Wardle that has in tying up the loose ends relating to the triplets in particular and the Neubauer study in general. He seemingly shares Bobby and David's conviction that Elliott did his best in rearing Eddy and that it's impossible to say whether he would still be alive if he had been placed with an easier going father. 

But, even though we might consider Neubauer's programme to be reprehensible (especially as he had fled a regime that had sanctioned similar, if more hideous, experiments by the likes of Josef Mengele), by judging it according to modern ethical standards, Wardle finds himself on shakier ground. There's no question that Josefowitz and Perlman are seeking to cover their own backs in rationalising Neubauer's hypothesis and methodology. But the lack of indictable evidence from the Neubauer archive leaves the waters looking as much muddy as murky and the film rather self-righteously pushes its luck in intimating that the 2066 seal has any sinister connotations.

By and large, however, Wardle does a decent job in drawing the audience into what remains a remarkable story. He also deserves credit for adding an investigative element to the talking-head reminiscences. At times, he makes irksome (over)use of dramatic reconstructions, with the decision to dub a voice for Eddy as Bobby recalls their first phone call being the tackiest of his missteps. Paul Saunderson's score also has a tendency to overplay its hand, despite it allowing Wardle to make some tricky tonal shifts, as the story turns from tabloid gold to the stuff of dystopic science fiction. But, that said, Michael Harte's cutting of the footage of Brenda and Eddy's wedding to Billy Joel's `Scenes From an Italian Restaurant' reveals the deftest of touches.

It takes considerable courage to make a documentary about one's own life, as privacy goes out of the window and complete strangers get to view and form opinions about one's habits, choices, actions and emotions. When the subject is as deeply personal as the one that transgender film-maker Jason Barker addresses in A Deal With the Universe, spectators can feel like snoopers, especially when the images are filmed in such a confined space and have such an unapologetically home-movie vibe. 

Barker didn't begin recording his attempt to have a child with his partner, Tracey, with the intention of making a feature. But the video clips kept amassing after Tracey was forced to give up IVF treatment after being diagnosed with breast cancer and Barker (who had transitioned over a decade earlier) decided to stop taking testosterone in a bid to become pregnant. Even then, several years passed before he returned to the footage and opted to shape it into a narraative with the assistance of editor Rachel Meyrick and Hope Dickson Leach, the director of The Levelling, with whom he had worked on the short, Silly Girl (both 2016).

Capturing the depth of the wonderful couple's love for each other, the resulting actuality is moving, inspiring and beautiful. But it's also far too intimate for a critic (especially a squeamish one who doesn't possess the sharing gene) to have the temerity to comment upon in any detail. Therefore, instead of assessing the content - and the role played in it by various cats and window-box pigeons - we shall merely make you aware of its existence and encourage you to seek it out, either on disc or your preferred VOD outlet.