A worldwide community photographing and learning about wildlife
It looks like some variation of the wood-sorrel Oxalis triangularis, also called Purple Shamrock (the one in the background definitely looks like O. triangularis), but I've never seen it this pale purple before! Very cool, where exactly in London did you find it? Growing in a container/garden? They're very popular as potted plants because the cultivar has such striking leaves. Neat find :)