John Mills, who works as an importer, was having lunch with his wife Gill, a recruitment consultant. Mr Mills said: "I hate the idea. We go to a lot of restaurants already where there is a service charge included in the bill and if you get terrible service you have to have a major altercation not to pay it."
Mrs Mills also preferred to tip at will, but for a different reason. "If you get really good service you like to tip more. We understand waiters depend on tips."
Their waitress Patricia Movillo, a student from Argentina who works at All Bar One to finance her degree, said she liked to be tipped for good service. "It is good to have tips because you get cash and that is nice pocket money. If you give better service you are given a tip - it's common sense," she said.
When she started at All Bar One a year ago she earned pounds 3.60 an hour. That has now gone up to pounds 4.60 and waiters can earn up to pounds 6 in tips on a good lunch time.
Even so, waitress Helen Walker - who earns pounds 4.10 an hour - said she would prefer an increased steady wage. "I don't make an awful lot in tips," she said. "You can't really rely on them. Sometimes you expect to get a lot and you end up with nothing. I would rather have a straight hourly rate."
Stephen Neil, who runs a wine business, also thinks there is merit in scrapping discretionary tips. He said: "It is a better way as far as the client is concerned. You should be able to get up and go without the embarrassment of trying to decide how much to tip. You don't have to impress the girlfriend, and if the waitress pulls faces at you, you can tell her to get stuffed."
Joe Green, a management consultant, said compulsory service meant a costly tip if the meal was expensive. He said: "The fact that you are paying more or less shouldn't change the service from the waiter."
His server Nick Hamley, an Australian, who has been working at All Bar One for three months to fund his travels, said: "I think it is a little bit unfair to end tipping. The hospitality industry is almost based on tips and service. You go out of your way to look after people and it's like a reward."