A gang has been stealing private school bills from doormats in Hampstead and doctoring them to make unwitting parents pay thousands of pounds into the fraudsters’ accounts, police have warned.

Several residents in Hampstead say they have witnessed suspects rifling through post after gaining access to communal hallways. Others have had their bank accounts raided after cash cards and pin numbers were stolen.

At a meeting of the Frognal and Fitzjohns safer neighbourhood panel last Tuesday, ward sergeant Ailsa Naish said detectives believe a gang is operating in Hampstead stealing post after gaining entry to homes.

She said: “It appears they have altered bank details on school fees invoices and then posted them back in. Theatre tickets have also been taken and resold on ticketing websites.”

Panel chairwoman Jessica Learmond-Criqui told the meeting how one family’s nanny, in a converted house in Redington Gardens, spotted a suspect rifling through post in the hallway.

“The mother was later looking at the school fees bill and noticed it didn’t look right. She telephoned the school who told her that the account number on the letter had been doctored,” she said.

In a warning email another victim wrote: “Our post and building keys have been stolen on several occasions by a man who has a car with a driver waiting outside for him while he shuffles through the letters. He managed to steal a new Barclays card and pin from one of the residents of our building, and scammed about £2,300 from her account. The same two men have also been seen to enter a building on Bracknell Gardens, from which they stole a credit card and a sim card for a mobile from one of the residents there.”