In New York it's customary for customers to leave a 16.5% tip, a figure arrived at by doubling the state's tax. Customers invariably follow this rule. The position is equally well understood in France - service is included.
The position in London is more confusing but increasingly accepted.
Most restaurants now charge an optional gratuity of 12.5% - whether it's really optional is neither here nor there. Some charge more, some even add a cover charge. And a few leave the matter entirely to a customer's discretion. In an ideal world this last option would be preferable since a tip is supposed to be just that - a mark of gratitude for something above what was expected.
But the difficulty is that on larger tables, say a table for six people, where the bill might be £300 or £400 or more, it's not uncommon for a group to leave a tip of only £20. In isolation this is generous, but in the context of a large table and the work that goes into looking after it, not so.
Waiting staff should be paid fairly and well. Whether that comes from the restaurant directly or from a combination of the restaurant and the customer seems to me to be a false distinction since at the end of the day, the customer pays either way.
What to do about service charges - if there is indeed a problem - should not be distracted by issues around tax either. That optional service charges are exempt from VAT is to the benefit of the customer and no one else. We are all customers, so thank heaven - or should I say Gordon Brown - for small mercies. Optional service charges also have the benefit of not attracting national insurance contributions, so restaurateurs and waiting staff also benefit.
It seems to me that the current system, for the most part, works. Legislation to change or clarify the situation is not the answer. A better way to deal with restaurants that apply a service charge and then leave a space blank in the hope the customer is tricked into paying twice, is to go somewhere else.
* Chris Bodker is chief executive of Image Restaurants
Over to you... Tip or service charge?
John Vincent, co-owner, Leon
"We have the same prices at lunchtime as we do in the evening, the only difference being that we offer table service during dinner. We add a 12.5% service charge in the evenings to reflect that. We need to cater for the increased costs of running the restaurant in the evening. We could increase the price of the food, but the service charge seems fairer and simpler."
Tim Bacon, managing director, Living Ventures
"On tables of six or more we charge service. However, with tables of fewer covers it's discretionary. That encourages waiters to target those tables and serve them as well as they can. If we were to introduce a service charge across the board, staff would know the tip was coming regardless and there wouldn't be the incentive."
David Moore, co-owner, Pied à Terre
"I think a service charge works to the advantage of the customer. It saves any awkwardness at the end of the meal or worries over working out the precise amount. Difficulties can arise when diners wish to leave extra at the end of the meal - Americans often want to leave more than 12.5% - but that isn't too much of a concern. The system is straightforward, consistent and fair."
John Campbell, head chef, Vineyard at Stockcross
"We leave tipping to the customer's discretion. The price they see on the menu should be the price they see on the bill. This isn't America, where waiters have to virtually pay for their station and are totally dependent on tips. It's the responsibility of the employer to make sure staff are well paid. Waiters shouldn't be reliant on tips."