London's lesser-known green spaces unlatch their gates this weekend (9-10 June) for the annual Open Garden Squares festival. 208 gardens are taking part this year, from the la-di-da oblongs of Belgravia and Kensington, to hidden roof gardens.
Our own recommendations include the Ismaili Centre roof garden in South Ken, St Dunstan-in-the-East (if you've never seen it), Drapers' Hall Gardens in the City, and the SOAS Japanese roof garden in Bloomsbury. The Brunel Museum Gardens are also worth a look, if only to get a ride on the model steam train.
Some of the gardens are freely open to visit, but to get into most of them you'll need an all-weekend pass for £9 (advance) or £12 (on the weekend).
The complete list of gardens, broken down by borough, can be found here.