The British Standards Institute (BSI) stopped short of calling for compulsory independent regulation.

But sales and marketing director Ian Harper said the industry had "monumentally failed" to get serious about the issue.

The not-for-profit organisation, home of the Kitemark, already runs a voluntary regulation scheme - but only 150 of the 18,000 eligible garages have so far signed up.

Last year there were 15,253 complaints about car repairs and servicing from independent garages to the UK's official consumer advice body Consumer Direct, up 11% on 2006.

And the Department of Trade and Industry (DTI) estimates that consumers lose £4 billion a year as a result of shoddy work and poor service.

Mr Harper said compulsion was likely to be met with resistance and it would be preferable if the industry could put its own house in order.

Various trade associations and franchises including the Bosch car service have all come up with regulatory initiatives. But Mr Harper said the advantage of the Kitemark was that it was independent from any commercial interests and it was focused on looking at how to prevent bad practice in the first place, not on ensuring channels to complain.

Obtaining the Kitemark is a stringent process. An audit of the business is carried out, "mystery shoppers" are used, and qualifications checked.

The cost of £1,500 a year, or £4 a day, was "minimal" when compared to the consumer-confidence it could bring back to the garages, Mr Harper said.