Construction minister Alun Michael this week launched TrustMark, a joint project backed by consumer protection groups and 25 trade bodies.

Up to 14,000 firms could gain TrustMark accreditation by the summer. Ten trade organisations are already licensed to the scheme and more than 100 firms are signing up every day.

Ian Livsey, chairman of the scheme, said: "The TrustMark badge says you're an honest, competent and professional tradesperson and your firm does a good job."

Research carried out for TrustMark showed that 38% of people claim not to trust tradespeople at all, and 65% said they were uncomfortable leaving them in their home alone.

The scheme's launch follows the failure of previous government-backed quality schemes.

Nick Raynsford, then construction minister, launched the Quality Mark scheme in 2000. But it was dropped last year in favour of the TrustMark project, after costing about £10m and attracting just 585 members.