The victim, identified only as Elizabeth by Fife Police, was this week duped by a heartless criminal who tricked his way into her home.

She said, “Whoever did this to me has left me more frightened than I have ever been in my life.

“But it also makes me so angry that someone could sink this low and I hope with all my heart that it never, ever happens to anyone else.

“This affects your whole life and, while it might serve to make people more aware that this type of thing does go on, it still beggars belief that someone could commit such a crime in the first place.”

Fife Detective Inspector John Muir issued this warning, “These callers take on all types of guises, ranging from those offering to carry out work, often at grossly inflated prices, to those which are causing us all particular concern at this moment in time, the ones claiming to represent an authority and trick their way into the homes of the elderly and other potentially-vulnerable members of our communities.

“Sadly, there has been a marked increase in exactly this type of offence in recent months.”

To counter the menace, Operation Watchman has been launched in Fife and officers will make use of HOLMES — the computer-driven Home Office Large Major Enquiry System — to collate and share information with other forces.

In recent cases, a blue Renault Laguna car has been seen at or near the scene of incidents, while a dark Vauxhall Omega car is believed to have been used by those responsible for a number of these crimes.

On a number of occasions, the utility these people have claimed to represent has been the Water Board.

DI Muir continued, “I would ask that people always make sure they check the legitimacy of all callers who, if bona fide, will be carrying identification papers and will gladly allow these to be scrutinised or checked thoroughly.

“I also advise that nobody lets strangers, or anyone of whom they are suspicious, into their homes and think long and hard before agreeing to do business on the doorstep.

“Anyone worried at all should never hesitate to contact the police and, if possible, a neighbour to assist.

“Neighbours too can play an important part by providing us with extra eyes and ears, keeping a watch over elderly people and others living nearby, and noting descriptions of anyone or any vehicle, especially registration numbers, which rouse their suspicion.”