Seven people were arrested this week in connection with a series of telephone frauds by bogus police officers in Essex.

Five men and two women were arrested on suspicion of conspiracy to commit fraud when detectives executed search warrants in north London.

Numerous phones and computers were seized during the operation headed by the Eastern Regional Special Operations Unit (ERSOU), formed to investigate hundreds of rapidly-spreading frauds across East Anglia.

In the scam, elderly and vulnerable people are told by con artists posing as police officers or bank staff that their bank accounts have been infiltrated by thieves.

The tricksters claim they need to carry out forensic tests of the victim’s bank cards and PIN numbers, or receive large amounts of cash for examination.

In March, the scam hit this area when a Saffron Walden pensioner was tricked into handing over £5,000. Twenty four hours after that incident was reported, a man in his 70s, from Steeple Bumpstead, also fell victim to the scame and handed over £10,000.

More than 780 similar thefts and attempted thefts have been reported in Essex since January last year. The total stolen is more than £400,000.

Yesterday, four men aged 18, 21 and two aged 22, and two women aged 20 and 21, were being held at a police station in Essex and questioned about frauds in Essex and neighbouring counties. A fifth man, aged 23, was also arrested and quested at a London police station.

Detective Inspector Danny Lawrence, who leads the ERSOU phone scam taskforce, said: “These warrants further show how we are continuing to make the region a hostile place for anyone suspected of being involved in phone scams, which often target elderly and vulnerable people.

“Whilst we are continuing to make arrests, I would remind people to remain aware that phone scams are still operating across the region. As it does tend to be the elderly and vulnerable who are targeted by the offenders, please share the following advice with neighbours and relatives.

“If you are suspicious about a telephone conversation you should end the call and contact police via the non-emergency number, 101.

“Remember to use a mobile phone or a friend’s phone or wait at least five minutes before calling to ensure you aren’t reconnected to the offender.”