Insurance giants Aviva and More Than today revealed the cost of cover has soared for millions, as consumers were warned of further rises.

Aviva – Britain's biggest general insurance group – says it had driven through "double digit" increases in car insurance costs over the past six months, while also increasing home insurance rates.

More Than parent Royal and Sun Alliance (RSA) says it has hiked rates by up to 13% for motor and 4% for home cover.

Insurance available through brokers increased in cost by up to 37%, according to RSA.

Both firms reveal motor rates are rising faster than others as the sector seeks to improve profits.

This follows years of falling costs as firms tried to maintain market share as a greater number of insurers entered the fray.

Many in the industry also blame rising costs on increased instances of fraudulent claims and a "compensation culture" encouraged by ambulance chasers.

Costs to rise

RSA says it "continues to take action on rates as and when necessary", with expectations for premiums to rise further still.

However, Aviva says it resisted the pressure in previous years to reduce prices.

The rates blow comes as both firms reported half-year figures that cheered investors.

Aviva profits were up 21% to £1.3 billion in the first six months of 2010, while RSA's profits remained flat at £302 million, though this beat City forecasts.

Slash insurance costs

You can help limit the damage by following our car and home insurance system. Sometimes, the cashback you get is more than the cost of the cover, which can put you in profit.

Here's how it works:

Step 1: Combine the power of comparison sites. These zip your details to a host of insurers' and brokers' websites in seconds, scraping their data to report back the cheapest. No site lists every provider so the key is combining searches to give yourself the widest range in the least time to find the cheapest policy of those that contain your required cover (see the Cheap Car Insurance and Home Insurance guides for full details).

Also note, Aviva and Direct Line do not appear on comparison sites so, if you've time, search their sites to add to your comparison.

Step 2: Grab cashback. Once you know the cheapest provider, check whether you can grab any money back via a cashback website. These pay a cut of their commission if you click through to insurers' or brokers' sites via them (see the Top Cashback Sites guide).

Step 3: Remember next year. Just because you got a super-cheap quote this year, doesn't mean you will next year. So diarise a note six weeks before renewal so you don't up paying your insurer's expensive renewal price.

Comparison sites are not for everyone

If you have a medical condition, have a high claims history, if you are sharing a home with friends or you have any other complex issues comparison sites may not offer the cheapest policies.

If you can't find a decent quote, use a broker. You can normally find one via the British Insurance Brokers' Association (Biba) website (link below).

Additional reporting by the Press Association.

Further reading/Key links

Cut costs: Car Insurance, Home Insurance
Find a broker: Biba