Best vegetarian restaurants in London

LondonLite had a feature of vegetarian restaurants in London this week. Saf in particular, sounds very interesting, offering vegan and biological dishes (where food is cooked below 48 degrees C).

I haven't been to any of the restaurants featured, but I have tried Carnavale and The Place Below in the past. Root Master is next my list though, it's a vegan restaurant on an old London Route Master bus (geddit?), near Brick Lane.