Back in June I was in London for a friend's birthday party, and it happily coincided with Open Garden Squares Weekend. Very near where I was staying was Cranbook Community Food Garden (off Roman Road) and it was a delight - not really that large a space, created from a waste area that was not only an odd shape, but also originally had a small hill in it.
Three years, much hard labour and 1000s of tons of compost later, and it is truly inspiring - 17 raised beds, a wormery, a composting area and flowers, herbs, and vegetables ... all organic.
Surrounded by tall blocks of flats, it is sheltered and seems to be a suntrap - the runner bean plants were tall and already flowering gloriously, whereas mine up in North Yorkshire had only just started to twine up their poles.
I really like London and all it has to offer, and this would definitely be in my top ten of lovely things I have come across.