THE Tour de France is the big one. Two hundred competitors, an entourage of more than 3,500, millions of spectators and hundreds of millions of television enthusiasts.

For only the second time, it will come to Britain next year for two days of racing on the south coast between Dover and Brighton and on a circular route beginning and ending in Portsmouth.

A look at Channel 4's coverage of this year's tour, which will start early next month, will give a flavour of what is to come. For cycle racing, the impact will be enormous in a sport that is already building up a growing following in Britain.

But cycle campaigners are hoping that the hype, publicity and interest generated by the event will raise the profile of cycling generally at a time when transport planners are looking for pollution-free ways of easing traffic congestion.

Kellogg's has sponsored professional cycle racing since the mid- 1980s, during which time interest in the sport has mushroomed. Dr Kevin Yates, scientific and consumer affairs manager for Kelloggs, said the sport was competitive, tough and glamorous: 'It is relatively inexpensive to take up cycling and this accessibiliy has helped to encourage participation by all ages. Kellogg's spends a significant sum of money behind cycling each year. It is healthy, familiy orientated and fits well with the products we produce.'

Portsmouth, like Dover and Brighton, fought hard to attract the Tour de France to Britain and is keen to exploit its arrival to full advantage. Dave Knight, head of tourism at Portsmouth City Council, said the race ranked among the biggest sporting occasions of the year. 'There are lots of sound reasons why we want to be associated with such a premier event. The spin-offs are enormous and cycling appeals to a high-spending market.'

Besides using the tour to market the town to potential inward investors, other event organisers and tourists, the theme will be used in the city's schools as the basis for geography and maths projects.

Kent, which will see the first day's racing in Britain, is planning new cycle routes for the county to coincide with the tour and the large number of cycling tourists from home and abroad that it is likely to attract.

The European links emphasised by the organisers of the Tour de France are welcomed by the southern counties which have close ties with France.

This year's National Bike Week, sponsored by Hovis, another company aiming to benefit from cycling's healthy image, is stressing the bicycle as a means of transport. More than 400 events have been taking place to draw attention to cycling and its advantages as an alternative to car travel.

More than three-quarters of all journeys are under five miles long and half are two miles or less. Despite these small distances, the majority of trips are taken by car. If only a fraction were converted from car to cycle, the impact on congestion and the savings in fuel cost would be enormous, say Bike Week campaigners.

The objective is to lift Britain's poor cycling record in comparison to other parts of Europe. Only in cycling cities such as York and Cambridge is commuting at a level common in the Netherlands, Denmark and parts of Germany. Research conducted as part of the campaign showed that up to 10 million adults would consider taking up cycling or cycle more frequently if better facilities were available.

Rising sales, averaging 2m a year, mean one in three adults owns a bike, a 15 per cent increase since 1985. Environmental awareness, a desire to keep fit, traffic jams and better design are the reasons given for the growth.

Don Mathew, policy adviser to the Cyclist Touring Club (CTC) which now has a strong campaigning arm, said the political leaders of the new county council administrations had become a focus of activity in the driver for better facilities for cyclists. 'The CTC initiative is getting a very positive response. It is looking better than it has for a long while,' he said.

Spending of pounds 200m a year - a fraction of the road budget - would produce tangible results in terms of cycle routes, parking and traffic calming measures, according to the CTC.

Richard Morris, a Liberal Democrat councillor in Northampton, wants a national network of cycling councillors to co-ordinate activity. 'We want to improve on what we have at the moment and to make an impact in every district,' he said.

How cycling can contribute to easing urban transport problems is the theme of the Velo-City conference to be held in Nottingham in September. Some 600 delegates from 35 countries will hear of the latest developments in road design and planning, health research, and transport systems.