Kevin Jackson has written this splendid book - Fast: Feasting On The Streets Of London. (the image above is from the book, off of Amazon). Portobello books were kind enough to send me a copy.
It's splendidly enthusiastic about all the brilliant varieties of Fast Food you can get in London from kebabs to eels. (Though it's predictably sniffy about the corporate varieties.) It's dense with all the little facts you want to know about the histories of London's coffee houses, Milk Bars and chip shops. It has a nice line in mixing the trivial anecdote with the heavyweight academic reference and I really like the photography. You really get a sense of an author who likes what he's writing about, which meant I powered through it in an evening, using little sticky notes to mark all the places I'm very keen to visit. Top stuff.