A man from a village on the Suffolk/Essex border was conned out of hundreds of pounds when telephone fraudsters targeted more than 20 people in one day.

The man, of Dedham, was a victim of a long-running credit and bank card scam which saw him withdraw around £2,500 from a cash-point before his cards were stopped, Essex Police said.

A total of 21 people were targeted in the telephone scam between Monday and Tuesday, with 19 at properties in the south of Essex.

The other two included the Dedham incident and another attempted fraud in Steeple Bumpstead, near Haverhill.

Twenty people foiled the con when realising they were involved in a fraud scam, with only the man in Dedham being tricked by the callers purporting to be detectives from the Metropolitan Police or Essex Police.

Similar false names were used by the callers but their stories varied from claims that their victims’ bank cards had been cloned to claims that suspects had been arrested in possession of stolen bank cards.

Nearly 700 similar thefts and attempted thefts have been reported in Essex since the scam first came to light in January 2013. Similar crimes have been reported in the Met Police area and other counties.

More than 100 people in Essex have been tricked out of money and the total stolen is more than £355,000. Six people have been arrested in connection with the investigation.

Detective Chief Inspector Paul Maleary, of Essex Police, who is leading the investigation into the frauds, said: “These criminals are having a significant impact on some of the most vulnerable members of our society and sadly no individual is immune from this type of fraud.

“These thieves keep varying their stories and trying different tricks to encourage people to hand over bank details or large sums of cash.

“Fortunately our intensive media campaigns warning of this scam have been working well and the majority of people quickly hang up or tell the tricksters to go away in no uncertain terms. But one successful crime out of 21 attempts is one too many and we will continue to issue these warnings as long as these crimes continue.

“These offences are happening throughout the UK and Essex Police is now working with five neighbouring forces as part of the Eastern Region Special Operations Unit.

“All officers and staff at Essex Police have been fully briefed on procedures how to deal with these crimes and they have also been asked to help to spread warnings in any way possible.

“We are continuing to liaise with community groups and organisations to spread the word to elderly or other vulnerable people who are usually the targets for these thieves.

“We also urge all relatives and friends of elderly people to make sure that they are extremely wary of any callers claiming to be police officers or bank officials who want bank cards, PIN number or large sums of cash which they claim needs to be forensically examined.

“All their claims are absolute rubbish because the police and banks would never ask for details over the phone then send a courier to collect cards or cash.”