The scam involves a phone call to the victim to tell them that a police officer has someone in custody with their bank details.

The victim is then instructed to call their bank and notify them that they have been a victim of fraud.

The victim will then discuss their bank details over the phone - believing they are making a new call to their bank - but the fraudsters will not have hung up the original call and will attempt to remain on the line to impersonate bank staff and gather bank details.

Police are issuing the warning after three unsuccessful attempts to carry out the scam were reported to Greenwich CID on Thursday, 18 May.

In all three cases, the elderly people targeted recognised the scam and did not disclose their bank details.

Detectives from Greenwich CID continue to investigate the three reported cases. There have been no arrests at this stage.

Superintendent Lee Hill of Greenwich police said: "By sharing information such as this, we can continue to defeat these callous criminals.

"People should be aware that the police would never ask you for your bank details over the phone, nor for your PIN or bank cards.

"We would urge people to be vigilant at all times so they can avoid falling victim to a similar scam. Any suspicions should be reported to the police."