site unseen The RIBA Building, London

The Royal Institute of British Architects (RIBA) has been much in the news recently. Firstly due to a contentious dismissal, and secondly, much more happily, because of the Institute's plan to move its incomparable Drawings Collection into the Roundhouse at Camden.

Built as a turn table for railway trains in 1847, and then used as a warehouse before enjoying a distinctly chequered recent career as a music venue and arts centre, the Roundhouse would seem to be an ideal location to house the drawings of Sir Christopher Wren and many other architects. Whether this plan comes to fruition depends on the National Lottery.

RIBA's headquarters are in spacious Portland Place, sandwiched between the BBC, the Langham Hotel and Regent's Park. The purpose-built location was put up between 1932 and 1934 by architect Grey Wornum.

The interior is stunning, full of exquisite detail which deserves to be examined at leisure. Whether it be the marble columns, panelling and woodwork, or the decorative plaster and etched glass panels, this is a building that appeals both to the heart and the mind.

Perhaps the piece de resistance is the Florence hall, with its plaster reliefs which commemorate the craftsmen who worked on the building. Nearby is the sumptuous Dominion screen of Quebec pine.

By comparison, the exterior of 66 Portland Place appears austere. Made of Portland stone, it is dominated by the vast central window guarded by two tall columns bearing the figures of Man and Woman.

Look again, however, and you will see that even this simple but elegant outside is a far cry from the baldness of much post-war architecture. On the Weymouth Street frontage, for instance, the central figure high up above depicts Sir Christopher Wren.

But the glory of the exterior is rarely seen by pedestrians, namely the two massive bronze doors which are pushed back whenever the Institute is open.

The relief portrays "London's river and its buildings" and shows St Paul's, the Houses of Parliament, St James's Palace and much more besides. The three children swimming in the pool apparently represent Grey Wornum's own children. It is a neat and personal touch that sums up the virtues of the building, both inside and out.

The doors also act as a reminder that, when entering Aladdin's Cave, don't forget to look at the cave doors on your way in.

RIBA is at 66 Portland Place, London W1