TOMORROW at 6am, the first of 27,000 cyclists will set off on what has become the British Heart Foundation's single most successful fund- raising event: the London to Brighton Bike Ride. The cyclists all have sponsorship pledges and will be attempting to help the charity raise more than pounds 1m by completing the 58-mile course, which starts at Clapham Common and finishes at Brighton's sea front.

In 1976, when a group of 30 friends started the event, neither they nor the BHF could have foreseen the immense success of the ride. According to records from the BHF, the thousands of cyclists who have participated over the years have raised more than pounds 8m, and nearly a quarter of that ( pounds 1.91m) was raised in the last two years alone.

The ride has grown so much in popularity that it has qualified for inclusion in the Guinness Book of Records for having the UK's highest number of participants (based on the official attendance record in 1988 of 31,678 cyclists). This record number has been trimmed to 27,000 in recent years for reasons of safety from overcrowding. Getting a place in the event is now rather difficult: this year's registration was completed in a mere six weeks, to the disappointment of many would-be participants.

For John Smith, 71, from Southend-on-Sea, this year's ride is his 11th. 'I had my heart operation in 1980 and have been doing the London to Brighton now ever since, so it just goes to prove that (the BHF) is right. The fitness works.'

Unfortunately for the 284 victims of fatal heart attacks each day, this message may have come too late. But for many others, including those who were lucky enough to get a second chance, the message is one worth heeding, and they are riding to prove it.

For Mr Smith, cycling has become a habit for good health. The first time he did the ride it took seven and a half hours. Now, 13 years after his operation, he completes it in one hour less, but includes a half-hour tea break.

'I go swimming afterwards,' he says. 'I go straight into the sea from the finish. You can see the steam rising off the water.' He did a trial run of 40 miles in preparation for this year's ride, and intends to follow it with another one next week, supporting a charity for homeless children.

According to Mr Smith, there is an element of camaraderie among those who turn out, and many other cyclists have become familiar faces. 'I have seen whole families come back year after year. One couple rode on a tandem last year with their new baby on the back.'

The carnival atmosphere along the way makes the ride special and inspires many to come back for more. At certain points, entertainers play to the exhausted riders. One cyclist provides his own music each year by carting along a wind-up gramophone in the front basket of a butcher's bike. The drawback is that he has to push the bike up the hills.

For others, who have attempted the ride while unfit, the South Downs can defeat them, even on a good bike. In 1990, Michelle Hawkins, 27, from London, rode to Brighton with colleagues from work. The ride was enjoyable but she has not been back since. 'Although it was a beautiful day, it was so hot that the tarmac was melting. I hadn't cycled in about 12 years. I was able to reach the finish line, but it was incredibly difficult,' she recalls. 'Now, as a smoker, I doubt I would find it any easier.'

Even some of the most well prepared cyclists have their difficulties. 'Almost everyone has to get off the bikes at some point,' says Mr Smith. 'There are three places in the South Downs that are really tough. I always have to get off and push the bike up the last hill.'

Jeff Banks, fashion designer and Clothes Show presenter, has been keen on bikes since the age of eight. He was once a competitive cyclist and has trained and raced in France. But after a spectacular crash at Crystal Palace, that career was ended.

According to the story, he was sent skidding so far along the track that his clothes were completely torn off. 'I limped away with only my badly-scraped hands to preserve my modesty,' he now admits. 'Never wanting to repeat the experience of being undressed in public, I gave up racing in favour of a career in fashion.'

There are prizes awarded for those who raise the most money. But although many will have to cycle quite quickly to cach up with Mr Banks, who intends to finish the whole ride in one go, it is not a race. 'For the majority,' says the London to Brighton veteran, 'it's a fun day out spent visiting the many tea stops en route.'

(Photograph omitted)