It first opened 1857 and was hailed as one of the most remarkable interiors in London.

The Today programme's Laura Trevelyan got a peek at the revamped reading room

But over the years the original appearance of the room disappeared in several radical redecorations. Now, as part of an ongoing programme of work at the museum to celebrate its 250th anniversary, it has been restored to its original design as set out by the 19th century architect Sydney Smirke.

The restoration has included the repair of the unusual papier-mâché dome interior and the blue, cream and gold paintwork. The work is scheduled to be completed in the autumn. By then, more than 25km of gold leaf will have been used - one third more than was used in the restoration of Windsor Castle.

Some contemporaries of Smirke's considered the original decoration excessive, even by 19th century standards. Sir Frederic Madden, Keeper of Manuscripts, said at the time of its completion that the room was "a gilded dome... utterly unfitted for the real purpose of study".

Public reference library

For many years the room has been used only by post-graduate students - but when the renovations are complete in the autumn the general public are to be let back in.

British Museum archivist Christopher Date said: "It will be a public reference library, where all members of the public, when they come to visit the museum, will be able to come and consult books as well as multimedia facilities."