In the Grade II-listed landscape of Mayfair, London, you often have to wait for someone to die before you can move, renovate or expand. Then come the years spent wading through planning applications. So it's something of an architectural miracle that the Royal Academy has come to open its Keeper's House after a six-year redevelopment.

The east wing of Burlington House, built by architect Sydney Smirke in the 1870s, served as a residence for the 'keeper', head of the RA schools. But gradually the annex took on more staff, becoming a glorified office block. When, in 2002, the Academy acquired a new space in Burlington Gardens to house more galleries, a shop and, most importantly, offices, the RA recruited architectural practice Long & Kentish to redesign the original building. 'Getting the Burlington Gardens space is what unlocked this whole venture,' says RA chief executive Charles Saumarez Smith.

The new Keeper's House is a playground for 'friends', or patrons, of the RA - equipped with meeting rooms, lounges and a lower-level bar that opens to the public from 4pm until midnight. Rolfe Kentish transformed the three-storey wing - from the former wine cellars to the first-floor Academicians Room - using original features, including a wood-panelled wall scored with nail holes from a century of art hanging. He installed a new glass lift in a former lightwell to unite the entire scheme, and to serve VIPs away from the main traffic.

Still it's the lower level that Saumarez Smith and his colleagues hope will draw the neighbourhood's young creatives into the RA sphere (one can never have too many 'friends', after all). David Chipperfield (an RA academician himself) came on board to piece together the interior of the Shenkman Bar, bringing in phone-box red seating and a custom counter. On either side of an original service hallway, he's outfitted formal dining rooms with deep green walls, leather banquettes and historical details, like wood ceiling beams dating back 150 years.

On the walls hang a cross section of RA works, democratically selected by a committee of Academicians. They've also chosen to 'plant' one of Michael Craig Martin's giant red Pitchforks in the tiny tea garden, fringed with palm by landscape architect Tom Stuart-Smith. 'It's not big, but it's green,' says Saumarez Smith of the outdoor space. 'It's magical to have this right at the heart of London.'

TAGS: INTERIOR DESIGN, DAVID CHIPPERFIELD, ROYAL ACADEMY