A campaign warning consumers against being conned by dishonest mass marketing schemes has been launched by the Office of Fair Trading (OFT).

It said they are a growing threat and that around five million people have fallen victim to such scams as bogus competitions, lotteries, clairvoyants and pyramid schemes. The estimated cost to consumers is around £1bn a year.

“Scams steal money from the legitimate economy,” said OFT chief executive John Fingleton. “They are scheming, crafty, aggressive and malicious.”

However, IT expert Jan Prysbycki blamed the victims themselves. “You never get something for nothing and if a deal looks too good to be true then it probably is,” he said.