Now, this is a great idea.
The unused spaces are to be converted into vegetable gardens which would grow potatoes and brussels sprouts in an attempt to feed the 2012 Olympic athletes with home-grown products.
It is thought the flat roofs in London comprise an area 24 times the size of Richmond Park - and their owners will be offered incentives to convert their space.
As environmental awareness has grown, growing vegetables on allotments has become more popular across the country, although London still produces little of its own food.
We should be thinking more along these lines, quite an interesting idea, no?