Secretly kinky architecture!

When was the last time you stopped rushing around and became a tourist for the day? London may be one of the world's largest and most exciting cities, but many of its residents and workers act as though they lived in a drab Milton Keynes suburb, never pausing to take advantage of the stunning architectural heritage surrounding them.

But this month everyone who lives or works in London - as well as tourists - will get the opportunity to have a close look at more than 530 buildings, gardens and ruins as part of London Open House weekend.

Rowan Moore, the Evening Standard's architecture correspondent, compares the capital's architecture to "a secretly kinky civil servant", sporting frilly underwear under the sober suit. Whether or not you find the description attractive, it accurately sums up the unusual and wide range of building styles to be found in our city.

The event on 22 and 23 September will be the ninth year that the London Open House charity has offered people a chance to sneak a peek behind doors of buildings usually closed to the public. Admission is free to all locations.

And there is far more to have a look at than just a few grand ancient piles or venerable churches.

Twenty-eight local authorities are taking part, ranging from Westminster and the City of London to Enfield in the north, Merton in the south, Havering in the east and Hillingdon in the west, and the Evening Standard is tomorrow giving away a 66-page guide to help you pick the cream of their architectural crop to visit.

Victoria Thornton, director of London Open House, said this year's weekend included a record number of buildings that have never before taken part. "We have more than 100 totally new buildings opening their doors to the public for the very first time this year, which makes it even more worth people coming to take a look," she said.

"Open House is a fantastic weekend and I really would encourage people to come and have a look at buildings that perhaps they pass every day on their way to work and don't look at twice. Alternatively you could use the weekend as a chance to visit a totally new part of London, and discover its architectural treasures."

Well known central London buildings opening their doors include the Guildhall in the City and Erno Goldfinger's controversial Trellick Tower on Golborne Road, W10. The architect gave his name to the James Bond baddie after upsetting Bond author Iain Fleming with his modern design for a house on Willow Road, off Hampstead Heath.

Those with a taste for controversy - and any taxpayers wanting to see where their money has gone - might also like to pay a visit to Portcullis House, the luxurious new pad for MPs built opposite Parliament at a cost of nearly £250 million. Working out at a cost of more than £1 million per occupant, Portcullis House is the most expensive office accommodation in the world.

Art and science lovers will enjoy a tour of the RSA in John Adam Street, WC2, and for those fascinated by medicine the Chelsea and Westminster Hospital is offering visitors - who should book a tour in advance - the chance to have a look at its revolutionary 1993 building. Those with a taste for gore are advised that wards and operating theatres will not be open for inspection.