Telephone fraudsters are posing as council tax officials to try and obtain sensitive financial information.

Residents are now being urged to be on their guard after Sutton Council said the organised gang could now be operating across south London, with Sutton one of the prime areas on their hit list.

A council spokesman said the warning came after an elderly householder reported on Friday that he had received a telephone call from someone pretending to be a council tax official.

The caller claimed to work for Sutton Council and said he needed the man’s bank details because of a query over his council tax instalments.

Sensing that the caller was not genuine, the resident hung up. It came after a similar incident in Wandsworth the day before.

Julie Turner, executive Head of Business Services (Interim) at Sutton Council, said: “These calls are a complete and utter con.

“People should not be taken in by them – and they should never give any sensitive personal information like bank account details or their date of birth to people who ring up out of the blue.”

“No genuine council employee would ever make such a call and it would simply not be necessary for us to have your bank account details for this purpose.

“My advice to anyone who gets these calls is refuse to tell them anything at all and simply hang up.”

A spokesman said the council does not make refunds over the telephone. The council also does not determine which households are included within each council tax banding.