HOUSE builders have been urged to fit combined smoke and gas alarms in all new homes to prevent tragedies caused by faulty heaters.

Tom Levitt, Labour MP for High Peak, said carbon monoxide (CO) poisoning was a `silent killer' and blamed thousands of untrained gas fitters.

Mr Levitt told MPs in the Commons of two tragedies in his constituency in which four people, including two pensioners, died from carbon monoxide poisoning.

He said: "These deaths could have been prevented by electronic CO detectors. I hope the government will act to ensure a CO monitor is compulsory when every house is built."

In one tragedy Mary Bailey, 15 and Martin Taylor, 21, died in a house near Glossop in which a valve had just been replaced on a boiler. Mr Levitt said: "It had been incorrectly fitted by gas fitter Jason Barton."

A jury failed to agree twice on a charge of manslaughter against him for negligence and he was fined just £2,000 and had his Corgi registration removed.

About 36 properties where he had worked had gas installations which were `at risk' and a judge regretted that he could not send him to jail. Mr Levitt said British Gas estimated about 20,000 people carried out work on gas appliances, many of them untrained and others removed from the Corgi register for negligence or malpractice.

He added: "About 200 people a year survive CO poisoning but long-term damage includes kidney failure, heart attack and brain damage."

He urged the government to publicise the dangers to landlords and tenants and to encourage house builders to fit combined smoke and carbon monoxide alarms.

Work and pensions minister Anne McGuire said: "We need to reinforce the message that gas appliances should be regularly checked by a Corgi-registered installer."