With the dramatic advances in medical knowledge in recent years, it's now possible to live for a long time with what previously might have been described as a terminal illness. If you are diagnosed with a critical, or life-threatening, condition a critical illness cover (CIC) policy pays you a tax-free lump sum if you are not able to work due to your illness.

With the critically ill living longer and insurers therefore paying out more on these policies, the cost of premiums has been soaring. At the same time the cost of life insurance policies are falling as claims on those have decreased.

Top of the leader-board in terms of cost are Scottish Equitable and Norwich Union whose premiums rose by a massive 60 per cent recently. Next in line with 50 per cent increases are BUPA and Friends Provident. Those make Swiss Life's and Legal & General's 20 or 25 per cent hike look quite modest. Watch this space for Liverpool Victoria 's announcement of their price rise.

Two conditions which are being 'downgraded' by the Association of British Insurers are prostate cancer and some heart disease. Earlier diagnosis and better control mean that they are not necessarily life-threatening. As claims will be reduced by this action, so the premium costs should also be kept in check.

Broker LifeSearch's Kevin Carr explains, "Although this type of insurance was originally known as 'dread disease', many of the conditions currently covered by critical illness policies are becoming quicker and easier to detect and treat. Hence insurers have recently found themselves paying out on claims where the condition was not life threatening, which isn't the purpose of the policy."

Insurers will be re-examining their policy terms more often too. BUPA will be the only insurer whose CIC policy includes diabetes as Swiss Life is axing cover of that condition from its policy.

Reviewable policies are more common now too, with premiums and the state of your health being checked every five years. In fact now Scottish Widows' CIC policies are all reviewable and Skandia is going the same way too. L&G has brought out a reviewable policy but has still retained its guaranteed policy.

People with guaranteed cover shouldn't worry as their existing policies won't be swept away, and their insured conditions as well as the set term (usually the length of their mortgage) will remain in place. But people looking to purchase a guaranteed CIC policy, if they find one, will find it more expensive than the reviewable type - about 15 per cent more according to L&G.

"The reviewable price will be typically [around] 15 per cent lower than the guaranteed cover," says Ronnie Martin, protection director at Legal & General.

When all is said and done it's down to personal choice and your financial circumstances.

Liverpool Victoria 's Rye Mills, group director of LV 's independent financial adviser division, reckons that people will be driven by cost and will opt for the cheaper reviewable policies, even though 'there's a price to be paid for the peace of mind a guaranteed policy gives'.

LifeSearch's Kevin Carr on the other hand believes that most people would prefer a guaranteed policy.

Their advice is that, whatever you decide, you should sort it out now before there are further alterations to the terms brought out.