Seven people were arrested today when detectives executed search warrants in connection with a series of Essex telephone frauds by bogus police officers.

Five men and two women were arrested on suspicion of conspiracy to commit fraud when officers went to addresses in north London.

The operation was carried out by detectives, including officers from Essex, who are part of the Eastern Regional Special Operations Unit (ERSOU) a regional team that was formed in March to investigate the rapidly-spreading frauds by thieves posing as police or bank officials.

More than 80 officers from Essex, Hertfordshire, Bedfordshire, Suffolk, Cambridgeshire and the Metropolitan Police Service Police were involved in the searches of six addresses in the Camden area.

Six suspects, four men aged 18, 21 and two aged 22, and two women aged 20 and 21,are currently at a police station in Essex and are being questioned about frauds in Essex and neighbouring counties. A fifth man, aged 23 was also arrested and is currently being quested at a London police station. Numerous phones and computers were seized.

The regional team was formed to investigate hundreds of frauds and attempted frauds being carried out across East Anglia.

Elderly or vulnerable people were being targeted by thieves who posed as police officers or bank staff who told their victims that their bank accounts had been infiltrated by thieves.

The tricksters claimed that as part of their investigations they needed to do forensic tests of the victim’s bank cards and PIN numbers or large amounts of cash to be used for forensic tests.

More than 780 similar thefts and attempted thefts have been reported in Essex since the scam first came to light in January 2013, and similar crimes have been reported in the Met Police area and other counties.

More than 120 people in Essex have been tricked out of money and the total stolen is more than £400,000.

Detective Inspector Danny Lawrence who leads the ERSOU phone scam taskforce said: "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."

Your bank and the police would:

• NEVER ask for your bank account details or PIN number over the phone.

• NEVER ask you to withdraw money and send it to them.

• NEVER ask you to send them your bank cards or any other personal property.