Tate has announced that work on a £45m scheme to transform its original London gallery - Tate Britain - is to get underway in February 2011.

Designed to help conserve the Sidney Smith-designed building,, the scheme will also entail a major upgrade of the the Grade II*-listed attraction's galleries.

Caruso St John Architects' plans include the reconstruction of nine galleries in the southern part of the building and the revamp of its main entrance on Millbank.

The River Room - formerly a watercolour gallery divided into three offices - will return to public use as a single room, while new learning spaces and a café are also to be created.

Work is due to be completed in 2013. Drivers Jonas Deloitte is project manager, with Alan Baxter Associates; Maxfordham Partners and Turner and Townsend also involved.

A Tate Britain spokesperson said: "The project will remodel and renovate core visitor areas - opening up the stunning domed atrium at the heart of the gallery - while creating much-needed learning studios and public spaces in order to meet growing demand."

Image: Artist's impression of the new Tate Britain Members Lounge - courtesy Adrian König, Caruso St John; copyright Tate