Climb every mountain ...

As the summer holidays arrive many otherwise placid Britons will suddenly find themselves doing some ludicrously dangerous activities. Bungee jumping, white-water rafting and scuba diving are increasingly popular yet, according to the insurer Home & Overseas, one in three holiday makers fails to take out extra additional insurance to cover them.

Jumping off a bridge attached only to a stretch of elastic might suggest you are a bit mad; doing it without insurance would seem certifiable. A serious injury that disrupts your career could cause you financial as well as physical damage.

The good news is that many normal travel insurance policies will cover you for an activity done on the spur of the moment. For example, in its standard travel insurance policies, Home & Overseas covers jetskiing, parascending, scuba diving to 30 metres and waterskiing. Canoeing in calm waters is covered but not in white waters. Mountaineering, bungee jumping and parachuting are excluded - as are boxing and big-game hunting.

Cover varies from insurer to insurer, and high-street travel agents and tour operators are likely to have tighter exclusions. So if you think you might want to risk life and limb, check your insurance before you go.

If you are going on an activity holiday, for example a week dedicated to diving or rock climbing, you should arrange specialist cover in advance. The same goes for football and rugby tours.

Travel insurers such as Columbus Direct charge a supplement for certain activities, such as bungee jumping, sailing, hot-air ballooning and scuba diving.

Two weeks in Spain would cost you pounds 14 with Columbus, rising to just pounds 15.34 if you took its Action Adventure cover, which includes bungee jumping, scuba diving and a dozen other hobbies.

This buys you pounds 15,000 permanent disability cover, pounds 5,000 death cover, the usual cancellation and curtailment and pounds 1m personal liability. Columbus refuses to cover more dangerous pursuits such as hang-gliding, microlighting and mountaineering. For these, you have to organise specialist dangerous sports cover.

Sportscover Direct, a specialist insurer, combines non-professional sports cover with travel insurance and may be more appropriate for the dedicated adrenaline merchant. Its Venture Card offers insurance for individual trips as well as annual multi-trip insurance, which gives cover for up to 90 days' travel in a 12-month period. Seventeen days' cover for maximum- risk activities in the UK would cost between pounds 17 and pounds 30, depending on the level of benefits you choose.

For worldwide cover, premiums would range from pounds 88 to pounds 155. Annual worldwide multi-trip cover costs between pounds 150 and pounds 500, depending on benefits. All the usual travel insurance risks such as theft, cancellation and curtailment, and loss of baggage are covered. Medical expenses and personal liability claims will also be met, but there is little compensation for injury, disablement or death.

If you pursue a risky hobby regularly in the UK and are a club member, you may be able to get cut-price cover through that organisation. The British Hang-gliding and Parachuting Association, for instance, offers insurance through the Airsports Insurance Bureau.

With all cover of this kind you may have to meet certain safety criteria - for example, wearing the mandatory protective equipment stipulated by the appropriate sports governing bodies - before your claim is met. If you are only covered for amateur sports and are injured in a professional contest, your claim could be thrown out.

Sports insurance can also be organised through a broker, who will typically sell you a product such as that offered by Crispin Speers & Partners. This has annual policies with three levels of risk. Low risk covers around 50 different amateur sports ranging from surfing and aerobics to more obscure sports like bicycle polo.

Medium-risk cover includes football, hockey, parachuting and scuba diving. High-risk activities include American football, boxing, pot-holing, mountaineering, rugby, hang-gliding and so on. The annual premium for each level is pounds 100 but benefit levels are lower for the high-risk sports.

One recurring problem with specialist sports insurance is that the benefits may be seen as too small. If that is the case, additional cover should be considered through general insurance plans such as life insurance, income protection cover and critical illness cover, which may pay out in cases of death or injury. These can provide far greater levels of cover.

Certain sports and hobbies may be automatically excluded. Make sure your insurer knows what you get up to at weekends or on your holidays; non- disclosure is a common reason for refusing a claim.

Philippa Gee of Gee & Company, a financial adviser, says: "Don't just pick insurance with the cheapest basic rates; it may exclude your sport from cover, or charge a lot extra for it."

n Contacts: Airsports Insurance Bureau, 01983 298480; Columbus Direct, 0171-375 0011; Home & Overseas, 0171-434 3002; Sportscover Direct, 0117 922 6222.