Some churches in London run cafeterias to help support the church and some do it as a service for students and poor travelers.
One is St. Martin-in-the-Fields near Trafalgar Square. They have sandwiches, salads and regular meals. Food was quite good and prices cheap when I ate there. They are open for lunch and dinner. Hours vary.

They also have free noontime concerts some days.

Another church that runs a cafe more as a community service is very near Westminster Abby, no more than a block or two away, but I can't remember the name of it off hand. Lunch was very good, soup and sandwich, and very cheap. If I can track down which one it was, I will post it.

There are a couple of others, just don't remember which ones. Worth checking out.

I just looked on the Tower of London website to see about obtaining two tickets for the Ceremony of the Keys for September (wish me luck--I bet everyone who's read the National Geographic article has the same idea!).

If you do not have an English address, you are asked to provide two "coupon-response international." For Americans, these coupons can be bought for $2.10 each at the post office, but the terminology is slightly different. Ask for an "International Reply Coupon (IRT)."

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The British have totally mastered the art of the takeaway sandwich. They are my staple when I'm visiting London. Avoid getting crisps with it, which can cost almost as much as the sandwich.

Good value for London are small, all-you-can-eat buffets, for instance of Thai food. There are a number of these (and other good small cafes) in and around Charlotte Street, west of the Goodge Street tube stop, for example.

This last trip I was on a very tight budget, and packed along a small jar of peanut butter. With fruit and Melba toast from Tesco, this made a good morning or late-night snack.

If you have access to a fridge, cheese is a great value in the UK.

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