If you get a phone call asking for your bank card or PIN, hang up no matter how genuine it sounds – that’s the advice of Havering Police.

“Courier fraud” has hit every London borough, police said, potentially costing elderly and vulnerable people their life savings.

Det Ch Insp Phil Rickells of Havering Police said: “We want people to question even truly genuine sounding calls and, most importantly, remember police and banks will never ask for your PIN or bank card, so you should never give them away.”

Typically, fraudsters phone their victims claiming to be calling from an authority – usually the police, bank or Serious Fraud Office – notifying them their bank accounts have been “compromised”.

The most convincing part of the ruse is that the crooks then tell the victim to hang up and call the police, bank or Serious Fraud Office on a genuine number to confirm what they’ve been told.

But when the victim hangs up and dials the new number, the fraudster stays on the other end – so the victim simply ends up speaking to the same person or a co-conspirator.

After apparently “confirming” the details, the victim gives out his or her PIN, and agrees for a courier to visit to collect his or her bank card.

When the card reaches the crooks, they use it along with the PIN to empty the victim’s bank account.

If you know someone who might fall for this scam, tell them:

Police and banks will never ask for your PIN or bank card

You should never give your PIN or bank card to anyone

If you are contacted by someone who asks for your PIN or bank card, hang up

If possible, use a different line (such as a mobile) to report it to police on 101. Using the same phone line could mean the fraudster is still connected as the person who initiates a land line call is usually the only one who can terminate it.

Dial 999 on a different line if the crime is still taking place.