The FCA said the scammers were contacting people by email, post or by phone and claiming to be the regulator or an individual from the watchdog. The crooks are even using the regulator’s switchboard number – 020 7066 1000 – as a caller ID.

The regulator said consumers should not offer any information or call the fraudsters back and said it would never contact anyone asking for money or account details.

It said: “The correspondence is likely to be linked to organised fraud and we strongly advise you not to respond to the criminals in any way.”

It advised: “Look for signs that the email, letter or phone call may not be from us, such as it listing a mobile or overseas contact phone number, an email address from a hotmail or gmail account, or a foreign PO Box number. Scam emails or letters often contain spelling mistakes and poor grammar.”

If you are in any doubt about the authenticity of contact from the FCA, call the helpline on 0800 111 6768.