The emergency services on the Isle of Man will be busy this week as the small island is transformed from an easy-going, sleepy little haven, into a frenzy of motorcycling mayhem. The controversial TT races are upon us once again.

The challenging and unforgiving course will probably claim more lives this year, and once again there will be calls for the races to be banned, or at least more controls introduced. The debate rages every time another life is lost, but people still flock to the island in their thousands every year to sample the action.

Since 1907 the Isle of Man has been the road-racing capital of the world. For motorcycle racers nothing is more of an honour than to have competed at the Tourist Trophy (TT) races.

The course is physically and mentally gruelling. The circuit is almost 38 miles long, and, depending on the category entered, the race distance will be three, four, or six laps. This means that some racers will cover 226 miles at an average speed of up to 120 mph.

This might seem reasonable if the course was a purpose-built race track, but the TT course is an ordinary public road that runs through villages and over mountains. The obstacles encountered if a rider falls off include lamp posts, walls, kerbs, houses, and wire fences.

Examination of the death toll during the TT races since 1991 (see panel) shows that the number of casualties among racers is a small percentage of the total. The majority of injuries and deaths are among the visitors who ride high-powered motorcycles while trying to emulate their racing heroes.

On the Isle of Man there are no speed limits outside the town boundaries, so you can legally drive at whatever speed you want. This particular law (or lack of law depending on your point of view) is the most controversial one on the island during the TT festival.

The TT races are the biggest tourist attraction in the Isle of Man. Every year 40,000 people, of which thousands would be from Ireland, descend on an island that has only 70,000 residents and the revenue this generates is one reason why the races will not be banned. Guest houses and hotels are often booked one year in advance.

During the Sunday of race week, visitors to the island get a chance to ride the race circuit because the roads are open to the public for the whole day. This has become known as "Mad Sunday" because of the thousands of bikers who push themselves and their bikes to the limit on the circuit.

Traffic sergeant, Paul Bradford, says: "We have asked for an all-island speed limit but it gets knocked back by politicians." But several other measures have been introduced to try to reduce the level of accidents during the TT celebrations. One of the main contributory factors to the high accident rate in the past has been foreign riders forgetting what side of the road they should be riding on, resulting in head-on collisions. Now road signs have been erected all around the island in many European languages to remind riders to keep to the left, and the mountain section of the course is strictly one-way on "Mad Sunday".

Last year a German rider had a head-on collision with a van. Both the van driver and the biker were killed. The motorcyclist was taken out the back doors of the van.

Despite the calls for an all-island speed limit, the Home Affairs minister, Allan Bell, says: "The Isle of Man has always been more relaxed in its attitudes, and in return for the freedom which we offer, we expect the visitors to behave in a responsible manner." However the outcry at the level of deaths in the past few years, including those of two island residents last year, has forced the authorities to reconsider their position.

"One of the recommendations we've come up with was that we make a study of accidents over the next three years and collate the statistics to establish whether a speed limit would be appropriate," says Bell. But there are also fears that a speed limit would be difficult to enforce and would ruin the good relationship that the police have with the public. There are only 214 police on the entire island, so only 70 to 80 can be on duty at any one time.

"The Manx method of handling large numbers of bikers is often studied by police forces elsewhere because it is so effective," says Bell. "That effectiveness is only dependent on mutual respect, and once that is broken down the situation could run out of control very quickly."

Sgt Bradford puts this lack of trouble down to the inherent good nature of motorcyclists. He says the vast majority of visitors only want to enjoy themselves, and that everyone is well behaved.

"We get more trouble at football matches, where only a couple of thousand people arrive for one day, than we do during the whole of the TT," he says.

On a visit to the island last year tragedy struck within one hour of our arrival on "Mad Sunday". As we drove the mountain section we came around a left-hand bend and saw people running to the right-hand side of the road where two motorcyclists lay. It was obvious that they were both dead. Smashed fibreglass and plastic from their bike was scattered all over the road. A police investigation later found that the man and his female companion had tried to negotiate the bend at over 100 mph on a 900 cc Honda sportsbike. As the bike left the road the front brake lever hit a fence post, and the sudden stop flung the rider and his pillion into the wire fence.

Victims of accidents will end up in Nobles hospital in Douglas where staff have seen every possible kind of motorcycle-related injury. In Northern Ireland the main hospitals have become experts in gunshot wounds; in Nobles hospital, bike crashes are their speciality.

"We are very experienced in dealing with high velocity trauma," says hospital manager, Frank Inmann. "Medics come here for experience during the TT." The chief medical officer for the TT races, David Stephens, would not like to see the races threatened with closure. "It is a major part of the Isle of Man's heritage," he says. "The throttle always works both ways, and the vast majority of riders respect that."

In Stephens's opinion the races are one of the safest in the world. If you consider the distance travelled by each rider, the accident rate is not high, he argues. His team of medical officers and motorsports paramedics are trained in crash-helmet removal and life-saving techniques. A helicopter ambulance with £2 0,000 worth of medical equipment is used to get to accident scenes in a hurry and the average response time is only five minutes. Basic first-aid kits are located at 81 positions around the course, while advanced life support cases are placed at 49 locations.

It is difficult to come up with a solution to the death toll during the TT celebrations. Some of the motorcycling press hold events and tours on "Mad Sunday" that attract thousands of riders away from the race circuit and towards safer activities. One would think this could only be a good thing, but Sgt Bradford is quick to point out that if a lot of riders are diverted away from the circuit it leaves more room for the remainder to increase their speeds, due to a lessening of traffic.

Honda racer and several times TT winner, Philip McCallen from Armagh, says: "People should just learn to slow down a bit, it's not worth losing your life over." The professional riders like McCallen know all about the risks involved in racing in the Isle of Man. They believe racing is a personal choice; if the TT were stopped it would be similar to banning people from climbing Mount Everest, skiing, horse racing, or boxing. There is an element of risk in many sports, and the competitors are willing to take those risks.

But the antics of amateurs are affecting the image of the TT races and putting them at risk. Living legends such as 22 times winner, Joey Dunlop, from Ballymoney, Co Antrim, exist because they know the limit of their own capabilities.

Undoubtedly the TT festival will continue to be the highlight of the motorcyclists' year - professional and amateur alike. Between the races, street parties, and all-night entertainment it is difficult to cram any more enjoyment into a week without the danger of sensory overload.

Unfortunately, this weekend, somebody will probably pay the ultimate price for it.