Platform: As the Tour de France pulled out of London last week, more than €30million of sponsorship went with it. There are some big names among the 23 nine-man teams racing around the roads of northern France this weekend - Nike, Kawasaki and T-Mobile included, writes Richard Gillis

The obvious question is, given the drugs stories that plague cycling, why do they stay?

Price is one answer. Compared to other international sports, the tour is relatively cheap. In the event's top sponsorship tier, several companies are paying €4- €5 million. This compares well with Formula One, Champions League football and the rugby World Cup.

But to save the sport from financial meltdown, the cycling authorities are under pressure to deliver on their promise of banishing the dopers.

Operación Puerto, the investigation into drug taking in sport, has had a cleansing effect. The investigation listed Jan Ulrich, Ivan Basso and a number of other star names, who have either retired under a cloud or been banned. (Incidently, there were more footballers and tennis players than cyclists on the list of offenders).

There is still a way to go. Only yesterday, T-Mobile team rider Patrick Sinkewitz was ejected from the race following a failed test, leading to German TV boycotting the event. "We are dismayed. There are hard days ahead," said a spokesman for the sponsor.

If found guilty of doping, riders agree to pay the ICU (the world governing body) the equivalent of a year's salary in addition to serving the standard two-year suspension from cycling. British cyclist David Millar is racing this year after one such ban. He was quoted before the race, saying: "There comes a point, and I reckon we're there now, when sponsors are going to pull out and the sport won't be economically viable. We've reached a kind of endgame. It won't be ethics that brings this whole thing to a halt. It'll be money."

Research by the New York Times, commissioned before this year's tour, suggests that Millar is right. It showed that three of Europe's top races suffered large drops in total live audiences, with the Ronde van Vlaanderen in Belgium faring worst with a 77 per cent decline from 2006.

That fall in viewership hit the media value of cycling sponsorships, which were calculated at about 10 per cent of the cost of buying traditional advertising time in the same time slots.

Tracking six major television markets in the United States, France, Germany, Italy, Spain and Britain, the newspaper found that television coverage of cycling events started to drop off after the Floyd Landis affair in 2006, from almost eight and a half hours, to five and a half hours.

At the start of the 2007 season, Spain and Italy, two key cycling markets, dropped live coverage altogether.

So, the reasons for getting out of cycling are obvious. And the churn rate of sponsors in the tour suggests a good number are doing just that. Marketers tend to be risk-averse. When a sport attracts negative headlines, the default response is to get out.

But there are signs that an alternative approach might bring greater benefits both to the sport and the sponsors. For example, before this year's race, T-Mobile tried something different.

They retained their financial support for the team, but ditched other supporting sponsorship activity, such as TV break bumper media buys.

The money saved will go toward research into doping.

The German mobile giant's pink and black team livery has been part of the occasion for over a decade, in particular as the patron of Ullrich, tour winner in 1997 and Lance Armstrong's arch nemesis during the late 1990s and early part of this decade.

T-Mobile's move is certainly a neat bit of PR. But it shows an imaginative response to the problem facing cycling and several other sports.

Rather than being just there for the good times, sponsors can emerge as a trusted friend when the going gets tough.

Sponsors often complain that fans don't appreciate their overall contribution. This is true. Often a team sponsor is seen as a necessary evil by supporters, a superficial here today, gone tomorrow presence. By getting their hands dirty and immersing themselves in tackling big issues such as drugs, they might just get the love they crave.