A temporary export ban on a set of rare photographs of the girl who inspired Lewis Carroll's Alice in Wonderland stories has been extended until May.

The photographs of Alice Liddell, taken by the children's author and Oxford don Charles Dodgson, were sold to US collectors for about £600,000.

But a temporary export ban was imposed after campaigners fought to keep the images in Britain.

Russell Roberts, a curator at the National Museum of Photography, Film and Television in Bradford, said the ban had been extended until May.

A consortium of the NMPFT, the National Portrait Gallery, the Victoria and Albert Museum and the Museum of Oxford, is trying to raise £600,000 to keep the photographs in the UK.