A woman aged in her 90s has described how a "bloody horrible” thief posing as a policeman tricked her into handing over £800 of her savings - in a telephone scam that lasted for nearly four hours.

Mrs R, who lives in Basildon, declined to be identified but has spoken out to warn others of the fraud which has continued across Essex since January 2013.

She is one of the latest victims of the scam which has netted thieves more than £380,000 from about 100 victims in the county.

Mrs R described how she was left "frightened, upset and in tears” after the thief’s smooth-talking claims to be a detective turned to bullying demands for her to hand over cash.

The phone rang at her home at about 11.30pm on Tuesday April 2 and a kindly-sounding man introduced himself as Dc Barry James from Hammersmith police station in west London.

He told Mrs R to phone him back on 999 to prove who he was, which she did, and an ‘operator’ took the call and put her through. It was all part of the scam.

He then said that two boys had been arrested in possession of a bag that contained a number of bank cards, including one belonging to Mrs R.

"He knew my name and said that the boys had details of the savings accounts I have at two different banks.

”The man said he only had 24 hours to keep the boys in custody and that it was important to move quickly to gather evidence against them.

"He told me to withdraw all my money from one account and to put it in my safe at home so it could be checked for fingerprints. I told him not to be silly, because I didn’t have a safe. He then told me to go to my banks and take out £5,000. I told him they would never let me have so much money, but he insisted that they would.

"He then said there was a taxi outside to take me to my banks in Basildon and sure enough there was a car outside. The driver took me to my banks, but they both refused to give me that amount of money without five days’ notice.”

Mrs R returned home and the man called her again. After she explained what happened he insisted that she should go back immediately to try again.

The same taxi driver was again waiting and for a second time both banks refused to let Mrs R withdraw £5,000.

"When he called again he became quite cross with me and said that it was my duty to help the police to lock up two thieves. He said I had to go back and keep trying to get the money.

"On the third occasion a different driver came and took me to a cash machine where I stupidly took out £500. When I got home the man phoned again and was really annoyed when I said I had £500. By this time I was tired, frightened and very upset.

"The driver then took the £500 which I had left on the table. He also took my bank card which was on top of the money.”

Mrs A later discovered that the card was used to withdraw a further £300 from one of her bank accounts.