Richard Harden, co-editor, Harden's Restaurant Guide, says it's all in the numbers - or maybe not

Words can paint pictures, but sometimes only numbers can tell stories. One of the simplest ways of telling the story of the London restaurant scene is by counting the number of new arrivals - and departures - each year.

At Harden's, we don't claim our figures are perfect - nor would any statistician - but, as far as we know, we are the only people who have been monitoring these details consistently for the past 16 years.

In this way, we have thus tracked the mid-1990s boom (when three restaurants opened for every one that closed), and the dog days in the aftermath of the second Gulf war - the only time that the openings/closures ratio declined almost to the 1:1 "replacement" level.

From our figures, the overall picture becomes pretty clear: there was a step-change in the mid-1990s, after which openings were pretty flat - around the 100 mark from 1996 to 1999. They bounced back again for the millennium, and have remained locked in a narrow range - 120-142 - ever since. Sounds pretty "steady as she goes", doesn't it?

What's much more interesting, though, is the percentage of restaurants that close from year to year. For all the time we've been tracking it, there's been an apparently inexorable cycle at work in the percentage of restaurants closing annually. It peaked in 1992, 1997 and the infamous annus horribilis in 2003.

You don't need to be Carol Vorderman to realise that there's a pattern emerging here. The two complete cycles to date (1992-97, and 1997-2003) have followed spookily similar paths: after the peak, closings fall for two years then make a ragged ascent, over three or four years, to the next peak.

Since the last peak in 2004, we've had three years (not two) of falling closings, but it does seem that the cycle is now due (even overdue) for a turn. If that's right, the market is now set for potentially three years of rising numbers of closures.

Of course, the past may be no guide to the future at all, but we wouldn't like to bet on it.

Do you think the restaurant boom is over?

Gaby Huddart, editor, Square Meal
Definitely not. The list we have of new places to review is literally as long as my arm. Places are not closing any faster than normal. There is the usual weeding out of restaurants that have either had their day or didn't quite do their sums right. We have an "RIP" file for places that have closed, and it's no bigger now than usual.

Kirsten Falk, general manager, Kensington Roof Gardens, London
We are definitely in the middle of a boom but we are very dependent on what happens around us, so if there are any terrorist issues or other instances like that, we will be affected. I think the boom will continue for most people, as long as the political and economic atmosphere remains stable.

James Grant, general manager, Wiltons, London
Restaurants will continue to open and restaurants will continue to close at the same speed, because owners need to grasp what customers want in order to build a regular client base. Wiltons has done well for more than 200 years and is continuing to do well. The restaurant boom will, I think, continue.

Richard Shepherd, owner, Langan's Brasserie, London
I don't think it will ever end. There will always be somebody who wants to open a restaurant and just as many that close. I think there will be a lot of restaurants hitting the brick wall by the end of this year, but there are a lot of silly people out there who see the industry through rose-coloured spectacles and think of it as a glamorous option.