RESIDENTS are being warned of door-to-door salesmen offering cheap electricity for their pre-payment meters.

The scammers are charging �25 to charge up the pre-pay keys with �50 of energy but once the utility company detects the fraud customers are charged again.

Dozens of households in Brent have already been caught-out with more expected to fall victim as the winter draws in.

Jacqueline Carr, director of Brent Citizens’ Advice Bureau, said: ““These offers must seem very attractive to people already struggling with household budgets and rising fuel bills, but as with all ‘too good to be true’ offers this one will cost you more in the long run.”

To make matters worse, any existing credit on victims’ keys is deleted when the fraudster charges it up.

People are being advised to only charge-up their keys at reputable sales points such as post-offices and shops displaying Paypoint or Payzone signs.

Ms Carr said: “If you have bought credit from someone who you now think may have been bogus, then we would recommend reporting it to the energy company as soon as possible as they have said they will be sympathetic to those duped or call Consumer Direct on 08454040506.”