London's Open House weekend is the highlight of many an architecturally curious or just plain nosy Londoner’s year.

Every September for the last 17 years, the doors of London’s buildings, great and small, have been thrown open to the general public, allowing an inside look at some of the city’s most famous buildings. This year, the event takes place this weekend (18, 19 September).

So what should you see? Lonely Planet's London Commissioning Editor, Clifton Wilkinson - who was invited to the launch at that icon of London’s Swinging Sixties, the BT Tower - lifts the lid on a weekend of architectural treats in the British capital:

Our man at the Open House launch

Arriving just before sunset at the launch, guests had the chance to see dusk fall over the capital and play 'what’s your favourite illuminated landmark?' (ours was St Paul’s Cathedral, still holding its own against the ever-growing number of skyscrapers in the city).

After the speeches, the moment we’d all been waiting for arrived – the revolving floor was switched on and we were treated to the wonderful if disconcertingly juddery spectacle of a 360-degree view of London without leaving the spot. Equally entertaining was watching the look of confusion on people’s faces as they came back from the loos (located in the building’s non-rotating central core) and couldn’t find where they had been standing before they went.

To see the BT Tower yourself you needed to register weeks ago but there are still plenty of other highlights you can just show up on the day for.

Top of the picks in Westminster are the Foreign and Commonwealth Office on Whitehall, restored to its original glory a few years back, or just along the street take a peek inside Horse Guards at the Duke of Wellington’s office.

If it’s views you’re after then over in the city, the 34-storey Broadgate Tower will test your head for heights, or join the queues for a glimpse inside the groundbreaking Lloyd's Building (sometimes known as the inside-out building).

Churches normally closed will welcome visitors (head for Hawksmoor’s St George’s Bloomsbury with its unusual steeple or Wren’s masterpiece St Stephen Walbrook) and there are dozens of special walks taking place too, all guided by experts.

The event is city-wide so to see what’s happening in a specific borough go to

BT Tower: for one weekend only

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