Dynamic flute-playing frontman Ian Anderson explains to Tim Hughes why his latest work harks back to a hero of the 1970s

It’s early 1972. The Americans are busy destroying Indochina, Nixon has returned from an historic visit to China and, at home, a state of emergency has been declared as a result of a miners’ strike.

Meanwhile, a youthful-looking progrssive-rock band release a hit concept album based on a poem by a fictional child prodigy. The band are called Jethro Tull and the hero of the record is Gerald Bostock.

Forty-two years later, Jethro Tull frontman Ian Anderson is back with the latest installment of Gerald’s life.

The record, Homo Erraticus, finds Bostock, now a retired Labour politician, alive, in good health, and keen once again to write rock lyrics.

The album, which follows 2012’s Thick As A Brick 2, is a classic product of Anderson’s imagination, based, according to its own mythology, on an unpublished manuscript by amateur historian Ernest T Parritt (1865-1928). It looks at key events of British history with a series of prophecies and visions of past lives, with the stories told through a cast of characters including a nomadic Neolithic settler, an Iron Age blacksmith, a monk, a turnpike innkeeper and Prince Albert.

“Homo Erraticus is Latin for ‘The Wandering Man’,” Ian tells me. “It’s the story of all of us; the story of the migration of the species.”

Clearly the errudite Ian, like Gerald, has lost none of his eloquence.

“We are all from somewhere... somewhere else,” he goes on. “Note I say ‘migration’ not ‘immigration’. This is not an album for Nigel Farage.”

Why resurrect the character of Gerald Bostock? “For a little connectivity and continuity,” he says. “He’s an old acquaintance returning for the Tull fans of old.”

Ian, 66, who introduced flute and whistle to rock and earned a reputation for his dynamic shows which still see him balancing on one leg – celebrates Bostock’s return with a series of live dates, including Oxford’s New Theatre on Sunday, duiring which Ian will play the album in its entirity.

Split into three parts – called, respectively Chronicles, Prophecies and Revelations – the record finds not just Gerald but the very medium of the concept album itself, fighting fit.

“The concept album is alive and feeling tolerably well under the circumstances,” Ian says. “Beethoven did concept albums; the 9th Symphony was the biggest and best. Sergeant Pepper was well on the way towards the same notion.”

And what makes it such an engaging art form? “It’s like an eight-course banquet as opposed to a fast-food snack in the mall.”

Despite tipping his cap to the past, Ian insists the music is altogether quite different. “It has become more detailed and, I hope better played and arranged,” he says. “But the trademark elements are still there. On purpose.”

The show will include hits from his 45-year career fronting Jethro Tull and as a solo artist. However, he insists it is strictly not a Jethro Tull show; the artist playing under his own name.

“Using only the name Jethro Tull suggests that it is just an established older repertoire show, like if you go to see the Rolling Stones,” he explains. “If I am doing new stuff and trying to break new ground, then having my own real name to the fore might gently warn off some of the folk who only want to hear the old songs.”

He confesses to a little embarassment at the name altogether. “We had three names in the four weeks prior to being called Jethro Tull by our agent,” he says. “They were all even worse! Ian Henderson’s Bag Of Blues was the previous name, I seem to recall. Mr ‘Henderson’ would have been proud. Mr Anderson – my father – would have been terribly disappointed at the typo, though.”

I point out that the real Jethro Tull – an 18th century agriculturalist widely credited as the father of modern farming – studied at St John’s College, and developed his pioneering seed drill while living in nearby Crowmarsh Gifford.

“He is the rightful owner of the name,” he says. “I should go to jail for identity theft.”

Where do his ideas come from? “Somewhere in the subconscious,” he answers. “But a writer needs to dig them out. It’s no good waiting for the muse to visit in her own time. You have to go looking and meet her half way. I suppose I have a native intelligence but no more than most people. I just try harder, maybe. “Really, most musicians and writers could do as well or better than I if they worked at it. I can't drive a bus or stack shelves at Tesco, I’m useless at the Times crossword, and my Latin is mostly forgotten. Don't even mention algebra and quadratic equations...”

So what is he most proud of ? “Survival. Followed by the occasional certainty that I have done something better than I could have done it 10 or even 40 years before.”

And, finally, is the charactar of Gerald Bostock based on himself. “He is an invented character who has his own views and opinions,” he says. “I am his mere messenger boy!”

Ian Anderson plays the New Theatre, Oxford, on Sunday.
Tickets are £28-£32 from 0844 871 3020 or see gigantic.com/artist/ian-anderson