The largest single cash donation made to a university library in the UK has been given to Oxford University's Bodleian Library so the public can see its treasures.

Julian Blackwell, President of Blackwell's, has donated £5m towards the redevelopment of the New Bodleian Library in Broad Street.

The renovation, expected to start in 2010 and be completed in 2012, will transform the housing of the Bodleian's priceless collections and will open up its treasures to the public.

Dr Sarah Thomas, Bodley's Librarian, said: "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 for those doing advanced scholarly research."

The atrium that visitors will arrive in will have a glass frontage onto Broad Street, will contain a café, and will lead off into rooms with permanent public exhibitions, including four original versions of the Magna Carta.

The entrance hall of the redeveloped New Bodleian Library will be named Blackwell Hall in honour of Julian Blackwell.

The donation launches the fundraising campaign for the redevelopment of the New Bodleian Library building into a major research centre, and a significant new cultural centre.

Scholars, Oxford residents, and visitors will be able to view some of the university's greatest treasures.

The gift cements the relationship between the Bodleian Library with Blackwell's bookshop, the library's neighbour and long-established partner, which opened its Broad Street store in 1879.

The donation will be officially announced during the Bodleian Founder's Lunch tomorrow, an annual event honouring the memory of the Library's founder, Sir Thomas Bodley.

The Rt Hon Margaret Hodge MBE, Minister for the Arts, will attend the lunch.

The 400-year old Bodleian is globally acknowledged to be one of the greatest libraries in the world.

Its collections include the papers of six British prime ministers; a Gutenberg Bible; the earliest surviving book written wholly in English; a quarter of the world's original copies of the Magna Carta; the original manuscript of Frankenstein; and over 10,000 medieval manuscripts.

Mr Blackwell said: "The Bodleian is unique - it not only has the largest and most important university collections in the world, but it is leading the development of cutting-edge information services which are so vital to academic research."

John Goddard, leader of the city council, added: "I warmly welcome the proposal to make the New Bodleian - and the treasures of the University's libraries - accessible to Oxford residents and the public at large."

In December 2006, Julian Blackwell donated his father's outstanding collection of rare and scholarly books, begun by Sir Basil Blackwell in the 1920s.

The Basil Blackwell Library is an important contribution to the Bodleian Centre for the Study of the Book, a newly established European initiative that will be located in the renovated building of the New Bodleian.

The earliest complete book written in English, Gregory the Great's Pastoral Care, translated by King Alfred in about 890 AD, is another of the library's treasures.

In November, controversial plans to build a £29m book depository at Osney Mead, to help ease storage problems at the library, were turned down by the city council.

A planning inquiry is expected to take place in May after the Bodleian appealed against the city council's decision.