CONSUMERS can compare quotes from some of the leading car insurers for the first time after Britain’s biggest supermarket entered the comparison market last week.

Tescocompare will be the first site to include premiums from firms such as Churchill and Privilege, which have until now shunned such websites – and now we know why. Analysis of Tescocompare results suggests they work out more expensive than rivals.

All the brands are owned by Royal Bank of Scotland, which has 30% of the motor-insurance market and has been unwilling to let them appear on such sites.

However, Tescocompare is a joint venture with the RBS group, hence the firms appear on the site.

Insurers such as Nationwide, Lloyds TSB and Virgin Money, which are underwritten by RBS, have also been prevented from appearing on sites such as Moneysupermarket.com and Confused.com.

Research by Confused, one of the most widely used sites, reveals that in more than 30 searches, only one of the RBS brands came within the top five cheapest deals.

In most cases, a quote was either refused or a significantly higher price was offered. In some instances, RBS quotes were more than twice as expensive as other providers.

For example, Confused did a search for a 33-year-old male manufacturing-designer living in Hertfordshire (SG6), driving a 2002 Renault Megane 1598cc with a 28-year-old named driver. He was offered a deal by Swiftcover for £189.

The most expensive deal was offered by Nationwide, underwritten by RBS, with a quote of £1,167 - more than six times dearer.

The most expensive nonRBS brand was Norwich Union, which offered a quote of £408.

A similar pattern emerged with a search for a 39-year-old male stockbroker, living in London (NW1), with a five-year no-claims discount and driving a 2006 Audi A4 Avant automatic 2.0. He was given a quote of £536 from Elephant.co.uk.

The cheapest deal by an RBS brand was offered by Privilege, but it still came in eighth position in terms of price, with a premium of £634.

Churchill, Nationwide, Lloyds TSB, Tesco and Prudential came bottom of the table, which compared 22 firms. The most expensive quote was offered by Prudential with an annual premium of £1,140.

In only one scenario did an RBS brand come within the top five deals. This was for a 39-year-old male architect, living in London (NW1), with five years no-claims, and driving a 2006 Audi A4 Avant automatic 2.0.

Privilege offered a deal costing £634 but the cheapest deal was from Esure costing £615.

In all the tests, an RBS brand or underwritten firm came bottom of the list.

Debra Williams of Confused said: “RBS has never before allowed its brands to be compared on price-comparison sites, and judging by our initial analysis consumers haven't missed out.

“While RBS may be a good place to start if you're lucky enough to have an unblemished driving record, most UK motorists can find better prices from one of the smaller insurers and brokers.”

Williams said the profiles used to make the comparisons were picked at random and taken from searches made last Thursday on their website by ordinary members of the public.

Direct Line remains the only RBS brand that continues to escape direct scrutiny by comparison sites. The car insurer has made a point of not selling its products through comparison websites – even attacking them in its advertising. However, Virgin Media is a “white-label” of Direct Line, which means that the prices it offers are the same.

In the Confused research, the highest that Virgin Money came in terms of cost was 11th position.

Confused has also criticised Tescocompare because a quarter of the 30 brands featured on the site are owned by RBS.

“It is interesting that RBS owns Direct Line, the one major insurance brand that refuses to allow consumers to compare its prices via comparison services, and has recently been attacking sites just like Tescocompare,” said Williams A spokesman for RBS said: “Confused.com is fighting yesterday’s battle. This is about product and price comparison. If everyone bought the cheapest of everything then we’d all be eating baked beans from a white can.”

He added: “There may be customers who don’t want, or don’t need, to get the absolutely cheapest price, but are looking for features that make sense to the way they live. That’s their choice.”

Tescocompare went live last Friday and is expected to eventually offer home insurance, credit cards and loans.

Its entry into the price comparison website market comes less than two months after Moneysupermarket was floated on the London Stock Exchange.