Confused.com and EMB have launched a new quarterly car insurance price index which has revealed an average price increase of 12.7% in 2009.

Other key findings included females seeing consistently higher increases than males in 2009 with women in their 40's seeing their insurance rise by 400% when they added teenager/s to their insurance.

Those living in the West Midlands experienced the greatest rise in car insurance premiums, while the Scots and Northern Irish have consistently seen the lowest rises. In 2009, 25% of UK car insurance buyers used Confused.com

The average cost of the cheapest quote rose by 12.7% in 2009 with most of the increases coming in the second half of the year. Prices rose by 6.3% in the fourth quarter alone. As a result, the cost of the average policy has risen from £450 at the end of 2008 to £507 at the end of 2009.

The index is based on an analysis of over 12 million quotes for comprehensive cover and almost a billion prices from Confused.com since the end of 2006. The figures showed that while prices stayed relatively flat or decreased throughout 2007 and 2008, prices have been steadily increasing throughout 2009.

Peter Ablett, commercial director at Confused.com, commented: "Over 50% of people now buy car insurance after visiting a comparison site and the fact that these figures are based on a very high sample of real quotes means that the index gives an unprecedented insight on what is really happening to prices. It can drill down reliably, looking at what is happening to prices, depending on gender, age and geography or a combination of these factors."

Confused.com said there were some surprising winners and losers in the 2009 price rises. It added that women generally came off worse with 21-30 year old females seeing annual increases approaching 17% compared to around 13% for men of the same age. In monetary terms, premiums still lag behind young men, but the comparison site said they were catching up.

Regionally, Scotland and Northern Ireland have consistently experienced the lowest rises to premiums over the last three years. The West Midlands saw the biggest average annual rise in 2009 of 17.9%, although the three postcode areas with the largest increases are all in the North and North West - Bradford, Oldham and Bolton.

EMB partner, Karl Murphy, said: "Northern Ireland is a slightly special case, but overall the regional trends are entirely due to the cost of claims. You can't overlook the fact that Scotland has a different legal system to England and Wales where the practice of solicitors paying for personal injury claim referrals is not allowed."

The motivation for consumers to shop around to secure a good deal is unlikely to diminish in 2010 according to Karl Murphy.

"Last year the average car insurer paid out £1.20 for every £1 of premium they received. Insurance providers have been badly impacted by rising numbers of injury claims, and with no signs of a reversal in this trend and negligible investment income available to them, further price rises can be expected," he said.