Iris's young life is portrayed by Kate Winslet

Also in the collection of papers is a 1968 petition letter imploring Russia to withdraw its troops from Czechoslovakia which Murdoch had signed.

Stephen Bury, head of modern English at the library, said: "The current interest in her life and her writing is proof of the position in which she continues to be held in popular esteem, and the important place she holds in literary history."

The film opened in the US last month and has already been tipped for success at the Oscars.

Dame Judi has been nominated for a Golden Globe award, as have Winslet and Jim Broadbent, who plays Mr Bayley.

Murdoch won the Booker Prize in 1978

Dame Judi admitted filming Iris was not easy, especially as shooting followed closely on from the death of her husband Michael Williams.

After she completed the film she said: "It's been hard work, the hardest work I've ever done."

Iris Murdoch was born in Dublin in 1919 and studied in Oxford.

She became a Fellow of St Anne's College, where she lectured on philosophy and began to publish literary work.

Her work was prolific and in 1978 she won the Booker Prize for The Sea, The Sea.