Which? experts warn that people who respond to what seems like a harmless phone call risk having their bank accounts “drained” through a “nasty” scheme. The caller on the line may claim to be filling out a lifestyle survey, but they have no interest in the responses and are only focused on two things.

During the conversation, victims are at some point asked to provide their bank information, including the account number and sort code. However, that is just one part of what eventually becomes fraud, as targets also have their identity secretly ‘cloned’.

A Which? spokesperson explained: “While you answer the questions, this information is used to create a sophisticated AI-generated clone of your voice. This information is then passed on or sold to another criminal group along with your voice clone.”

Armed with these details and a realistic copy of your voice, fraudsters have everything they need to set up a direct debit in your name with a credible-looking company that is all just a front. They use the voice ‘clone’ generated from survey responses to bypass bank security measures and gradually drain funds, without some victims ever becoming aware, reports the Mirror.

The spokesperson for Which? said: “Nothing is flagged by your bank because the details are correct. Now your hard-earned cash is going directly into the hands of the fraudsters.”

How can I protect myself and others from this?

The simplest method to avoid falling victim to this is to refrain from answering unexpected calls — particularly those from unrecognised numbers. Picking up just one unsolicited spam call will most likely result in further calls, as it indicates to these cold callers that your number is active and legitimate, flagging you as a “live” target to be called again or passed on to other fraudsters.

Which? recommends that people consider speaking to their phone provider regarding call-blocking features. They said: “Androids have a setting called ‘Filter Spam Calls’ and iPhone’s have ‘Silence unknown callers’.”

If someone answers a call from a person claiming to represent their bank, the best course of action is to hang up immediately – particularly if the call was unexpected. Which? claimed that people can call 159 and ask to speak with their genuine banking provider.

The scheme directs callers through a series of options to connect them to the verified customer service department. Calling 159 in the UK is generally not free, but it is low-cost, usually equivalent to a national rate call. It is treated like a standard landline or mobile call, meaning it is often included in your provider’s “inclusive minutes” packages

To prevent scams from going undetected and claiming further victims, report the matter to reportfraud.police.uk or call 0300 123 2040. Even if the scam was unsuccessful and you were not defrauded of any money, it remains worthwhile to report it. Doing so could help alert others who may have already fallen victim, or risk becoming one in the future.