London has plenty of vegetarian-only restaurants many of them championing organic foodstuffs, and a quick search in Google will produce plenty of ideas, so you never have to see a piece of cooked meat all week.

If you are dining with carnivorous friends most restaurants will cater for vegetarians and will have at least a couple of dishes on the menu. Indian/Bangladeshi restaurants are generally fruitful, as they have plenty of traditional dishes. There are also many vegetarian Thai buffet places where you can eat somewhat unconvincing (but tasty) meat substitute grub for £5. These can be found on Greek and Old Compton Sts in Soho and Islington High Street.