Accidents do not just happen any more. In an increasingly writ- happy Britain, victims are ever more likely to find someone to sue. Ben Smoulders, wheelchair-bound after his injuries in a rugby scrum, recently won pounds 1m from the referee in charge of the game, whom courts found liable. As the summer events season gets into its stride, organisers need to think about the hazards which can turn a dream day into a nightmare - and perhaps insure against them.

Sometimes fate just seems bloody minded - as in Dartmoor last weekend. More than 1,000 teenagers taking part in the Ten Tors trek had to be rescued, many of them by helicopter, after storm-force winds, driving rain and snow flurries combined to produce the worst weather for 10 years. The Army, which had organised the event, had to call it off. No one could hold the organisers responsible for the weather - and the rescue itself was completely successful. But it is a reminder of how the best-run events can go sour.

People running charity barbecues, fetes or gymkhanas may be more concerned with heavy rain, which can cost them hundreds of pounds, than with insurance claims, which could run into hundreds of thousands. But they do happen. The marquee at one village fete collapsed recently, which brought in several claims for injuries and also damaged a couple of valuable roulette tables. Finally the insurers received three claims for psychological damage from people who had started to suffer from claustrophobia after being trapped.

"Name any type of event, and somewhere it has gone disastrously wrong," says Mark Bishop of Cornhill, one of the biggest insurers in the field. "We recently had to pay a claim after badly cooked food at a county fair caused a salmonella outbreak. Carelessness often causes trouble. One woman who had gone to a gymkhana in stiletto heels hurt her foot badly after her high heel went through a cattle grid, covered by a sack."

Occasionally insurers get two disasters for the price of one. A bouncy castle was blown over in a strong wind last year, not only injuring a child but damaging a set of antique motor cycles next to it. So bills were considerable.

In the past most insurers offered events cover, but some pulled out in the early Nineties after a heavy series of claims on what is low premium business. Cornhill, Commercial Union and Sun Alliance are three big companies which still provide it and many Lloyd's syndicates will accept the risk.

How much will the insurance cost? That depends partly on the type of event. Cornhill wants a basic pounds 70 for insurance up to pounds 1m for barbecues, fetes or flower shows lasting less than two days - the cheapest available. Organisers who want to take the belt and braces approach need only spend pounds 10 more to double the limit.

Gymkhanas, field events and donkey derbies cost slightly more. This time, insurance bills work out at pounds 80 for pounds 1m-worth of cover. Sponsored walks, fun runs and traction engine rallies come top of the range. Even for one day events, the liability bill can work out at pounds 100.

Liability claims have certainly risen since British solicitors were allowed to operate on a no-fault no-fee basis, where they are only paid if the action proves successful. Professional groups are taking note. After the damages were awarded against the rugby referee, the National Union of Teachers told members in any insurance doubt last week to stop supervising games until they had checked their employers had taken out liability cover for them.

Local education authorities do so automatically. But the NUT claims it may be a grey area in some grant-maintained schools or sixth form colleges.

Anyone with a house and contents policy has at least some liability insurance, normally up to pounds 1m-pounds 2m. But the buildings cover only applies to claims which arise from the property itself - if someone trips over badly fitting carpet and falls down the stairs breaking an arm, for instance. People injured by slates falling from a dilapidated roof will certainly have a claim, though insurers will not pay out if high winds in a storm happen to dislodge them.

The liability insurance is wider with contents policies and it will certainly pay for accidents in the house. One woman recently sued her husband, after he had failed to mend the defective lock on a window. Their baby had got through the window on to a flat roof. The woman had fallen off the roof in course of the rescue and was so badly hurt she has to live in a wheelchair - and sued her husband for negligence. She won her case and the couple's contents insurer has paid her a six-figure sum.

But the liability cover does not stop at the front door. It will apply if your carelessness in walking across a road leads a driver to crash into a lamp post. If motorists damage people, or damage property, third party insurance will always apply. A fallback provision applies, even if the car is uninsured, for a trade body - the Motor Insurers' Bureau - will then pick up the bills.

The basic liability insurance, which applies to almost everyone, is distinctly compartmentalised. It certainly will not apply to jobs or charity events. In a world where people are more inclined to sue, taking liability insurance even on small risks allows you to be safe and not poverty-stricken.