I have just been reading an article about the average restaurant bill in different world cities.
The most expensive used to be Tokyo, but this year it comes only third after London and Paris. An average meal, including a drink, tax and service for London diners runs to 39 pounds, (nearly $80) while a roughly equivalent meal would cost 35.37 pounds in Paris and 35.10 pounds in Tokyo (around $70).
Eating out in the United States is a relative bargain, leaving New York City diners only 19.30 pounds (less than $40). In Los Angeles, people could expect to pay 15.63 pounds (around $32) for the same.
An average meal at the London's 20 most expensive restaurants will cost diners 88 pounds (nearly $ Protected content still cheaper than the most expensive in Tokyo and Paris, where meals cost on average 102.86 pounds and 101.08 pounds respectively (around $200).
My advice: if in London go only to the best restaurants.