Over 200,000 people in the UK may have fallen victim to criminals who woo them online in order to steal their money.
Researchers from Leicester University discovered that amongst those surveyed one in 50 were aware, or had been the victim, of friendly callers promising the earth and then asking for money. The victims pay up but the promises turn out to be worthless.
Researchers believe that many cases probably go unreported.
"It may well be that the shame and upset experienced by the victims deters them from reporting," said Prof Monica Whitty.
A spokesman for BT Infinity denied the allegations.