Energy companies have uncovered a doorstep scam which seems to offer cheaper electricity meter top-ups.
Criminals are using cloned keys to top up credit illegally.
Some people are being offered £50 of electricity meter top-up for a cash payment of just £25.
This results in consumers paying twice, first to the criminal and then to their energy supplier who can always detect when they have not received payment for used electricity.
In response, energy companies together with Consumer Focus have created a national campaign, "Top up Safe", urging electricity prepayment meter customers to buy top-up only through official channels - PayPoint, Payzone and The Post Office.
Companies never sell electricity top-up door-to-door.
There is evidence of serious and organised criminal activity and we are urging customers not to get involved.
Police have also made arrests in connection with this activity. Over 120,000 households have been affected already.
Customers of all of the leading energy companies (British Gas, EDF Energy, E.ON, npower, Scottish Power and SSE) are affected.
For more information on the top up safe campaign please visit www.top-upsafe.com.