The BBC's June Kelly: "The advice is - don't take snap decisions"

Consumer Affairs Minister Dr Kim Howells promised stiff action against "cheats, rogues and cowboys".

He said there was a worrying number of sellers using "high pressure sales tactics" to persuade vulnerable people to give them their money.

"Our campaign will inform consumers about how their legal rights have been strengthened to tackle this growing problem as well as reveal some of the tricks of the trade used by these conmen," said the minister.

The BBC's Emil Petrie: "A steady increase in complaints"

The law has recently been toughened in new Doorstep Selling Regulations which entitle consumers to a seven-day cooling-off period on most goods and services bought for �35 or more.

The changes apply unless the seller invites the salesperson to visit their home and traders also face a fine of up to �2,500 if they do not tell customers of this right to cancel.

They apply to a wide range of goods and services commonly sold on a door-to-door basis including:

• Building repairs excluding large scale extensions
• Double-glazing
• Burglar alarms
• Surfacing drives
• Gas and electricity supplies
• Repairs to roofs and gutters
• Fire extinguishers
• Vacuum cleaners.

Dr Howells' department said many people had been exploited, including a 63-year-old Preston man who signed a double-glazing contract after more than four hours' high-pressure selling.

"It didn't matter how many times I refused to sign the contract, the salesman just wouldn't go," said the man.

"In the end I gave in because I was exhausted and it was the only way to get him out of my home."

Scared into alarm

There was also the case of a woman who said she was "scared into" signing a contract for a �3,000 burglar alarm.

"The majority of traders who sell on the doorstep are decent, law-abiding individuals just trying to earn an honest living," said Dr Howells.

"However, there are too many who are targeting elderly, housebound and vulnerable people with their high-pressure selling techniques."