The ceremonial opening of the New Bodleian Library in 1946 by George VI is still remembered for the highly embarrassing moment when a silver key broke in the lock of the building’s ‘front door’.

In a way it proved a highly symbolic moment. For that heavy door on Broad Street has pretty well remained locked every since, with the New Bodleian viewed ever since as gloomy, inaccessible and unloved by locals and visitors alike.

At least the library has inspired local writers to compose some acidic observations.

For Howard Colvin, author of Unbuilt Oxford it remains “like a dinner jacket made of Harris Tweed”. Jan Morris reckoned: “If you are in your fifties, nothing will reconcile you to the Bodleian extension at the end of Broad Street, which looks like a well-equipped municipal swimming bath, and replaced a nice corner of jostling old houses in the late 1930s.”

The crime being made all the worse because those “jostling old houses” happened to be timber Tudor buildings.

You might have thought the challenge of creating a new building across the road from such architectural gems as the Sheldonian Theatre and the Clarendon Building might have brought out the best of the New Bodleian’s celebrated architect, Sir Giles Gilbert Scott.

But even he seemed reluctant to talk up his contribution to one of the city’s most beautiful and historic streets, writing on the eve of its opening: “The new library building is primarily a bookstore and consists of a vast central stack with rooms ranged round the outside.”

He almost might have added, to borrow from the world of TV advertising: “It does what it says on the tin.”

And perhaps the New Bodleian would have been destined to remain what for many is the spoiler of views from the King’s Arms (with the Broad Street frontage hardly improved by a metal rail added to combat the arrival of skateboaders), if it were not for the fact that the New Bodleian has stopped being very good at what it was built for: storing valuable books.

For a disturbing situation developed, in which millions of the Bodleian’s valuable volumes are being stored in a building that is, at best, far below national standards required for the storage of special collections, and, at worst, a fire risk.

Making the New Bodleian worthy of its world famous collections of precious manuscripts, books and maps is not going to be cheap, with the renovation of the building to cost £78m and building and remodelling work to stretch over five years.

But the scheme has also created the opportunity to finally make the New Bodleian a part of Broad Street and an altogether more welcoming place, offering proper public access to the Bodleian’s great treasures.

Richard Ovenden, associate director and keeper of special collections, said: “The New Bodleian was built essentially as a huge book fortress.

“The architects Wilkinson Eyre Associates have created a stunning design that respects the building’s heritage, while at the same time providing better facilities for students and researchers, as well as greater opportunities for collaboration with the local community and schools.

“Because of the nature of how the original building was built and the passage of time, the scheme is going to be very expensive. It will be a £78m project.

“But this is a great opportunity to deal with some of the core issues and modernise the infrastructure of the building. We will need to move over 3.5m books out of the building before work begins.“ This process is already under way, with the majority of high-use volumes and special collections to be transferred to the Radcliffe Science Library, thereby ensuring that high-value and high-demand volumes remain in central Oxford.

Gilbert Scott’s library, completed in 1940, had been judged to be an innovative design at the time, consisting of 11 floors. As Sir Giles recorded, the main problem was providing “a vast book-store on a limited site in a building that for aesthetic reasons had to be kept low enough to confirm with the general height of neighbouring buildings”.

The answer was to go underground, with four of the floors, which house 60 per cent of the bookstacks, below ground level. Given that the water table sits close to street level for much of the year, it effectively means the Bodleian’s books sit in a tank, effectively lying in a lake.

The New ‘Bod’ is home of the university’s rare and special collections, yet over the years the facilities have been demonstrably inadequate in terms of space, temperature and humidity controls, fire safety, and flood and security protection.

The extent of the problems became shockingly clear a few years ago when the National Archives felt obliged to question the future of the Bodleian as an approved repository for housing archival collections of national significance, with it no longer judged to meet the National Archives’ standard for record repositories.

The renovation work will see the removal of the massive forest of steel columns that Sir Giles put at the centre of his structure, with the unprotected columns presenting a fire risk that would be totally unacceptable in any modern library, never mind one that happens to store a Gutenberg Bible, the earliest surviving book written wholly in English, two Shakespeare first folios, the original manuscript of Frankenstein, the papers of six British Prime Ministers and more than 10,000 medieval manuscripts.

The project will also involve the replacement of the central stack, the development of three floors of secure storage below ground level, the provision of additional reading rooms and the creation of dedicated floors for curation and conservation.

It should be emphasised that Sir Giles Gilbert Scott was recognised as a great architect at the peak of his powers when he took on the New Bodleian. The grandson of Sir George Gilbert Scott, he is known for such buildings as Liverpool Cathedral and Battersea Power Station, and for being the creator of the red telephone box, perhaps the ultimate British design icon.

Some of his other buildings in Oxford, like the grade-II listed Hartland House at St Anne’s College, are still widely admired. St Anne’s is going to great pains, with its current £10m development proposals, to make their own Gilbert Scott building visible from Woodstock Road.

Mr Ovenden says the renovation scheme will respect the best aspects of the New Bodleian, while removing an ugly addition to the library which added precious little to Sir Giles’s original design.

The upper floor reading room created by the architect was never used for its original purpose.

Then, to make matters worse, in the 1960s, to create extra space, an extension was built at the top of the building. This will be pulled down, allowing Sir Giles’s original windows to be seen.

The renovation will also see the New Bodleian improved as a major research library, having become a place, that for all its international reputation, can appear gloomy.

But it is on the ground floor that many will detect the real shafts of sunlight, with the creation of exhibition galleries and learning spaces.

Bodley’s Librarian Sarah Thomas said that Bodleian exhibitions already attracted about 100,000 visitors a year, a remarkable figure given the limited exhibition space. The new exhibition rooms should bring about a significant increase in visitor numbers, with school visits encouraged.

She points to the fact that limited space meant an exhibition of Tolkien’s original drawings for The Hobbit will be staged only for one day (March 4).

She said: “The new facilities will give us the opportunity to put Tolkien’s drawings and the Magna Carta on show permanently.”

The Bodleian, in fact, holds almost a quarter of the world’s original 13th-century manuscripts of Magna Carta.

When its four copies of the Magna Carta went on public display for the first time in 800 years in the Divinity School for one day in December 2007, the huge queues showed the extent of public interest.

A donation of £5m from Julian Blackwell, the largest single cash donation ever made to a university library in the UK, has been key to helping the library progress its plans to open up its treasures to the public.

The entrance hall of the redeveloped library will be named the Blackwell Hall in honour of the president of Blackwell’s, the famous Oxford bookseller, which has been the Bod’s neighbour since 1879.

“Julian Blackwell’s gift will help transform the New Bodleian from a book fortress into an inviting and inspiring space for readers. The Blackwell Hall will welcome visitors to exhibitions and events that celebrate the book, and will serve as the entrance to the New Bodleian,” Dr Thomas told guests, when the donation was first unveiled.

The new glass frontage facing out to Broad Street will encourage people to enter a building that for a long time seemed to present its back to The Broad.

“People will even be able to see books from the street,” said Dr Thomas.

The atrium will contain a café and will lead off into rooms with both permanent and temporary exhibitions.

With a planning application going to Oxford City Council later this month, Dr Thomas said she was hopeful of a positive response from the Town Hall, having earlier seen the Bodleian’s application to build a £29m book depository on the Osney Mead industrial estate turned down. The depository is being built on the outskirts of Swindon.

When she first arrived from America to oversee the biggest expansion in the Bodleian’s history, she had assumed the creation of the depository would be “the boring part”.

But that was before being introduced to the workings of local government in Oxford.

But now comes the opportunity to write a new chapter in the library’s 400-year history where it really matters — in The Broad.

At the ‘new’ New Bodleian Library, only the George VI Door is destined to remain closed.