Card fraud prevention specialist Retail Decisions today said it had signed a two-year contract with BT Cellnet, the UK mobile phone division of the telecoms giant.

The risk management contract will see Retail Decisions provide payment card authorisation services designed to stop credit card fraudsters buying calltime on BT's Cellnet prepay mobile phones.

It follows a successful trial with Retail Decisions and adds to BT's existing work in fraud prevention. The contract is also Retail Decisions' first link with a mobile phone operator, having previously concentrated on fixed-line telecoms providers.

Carl Clump, Retail Decisions chief executive, said: "We are very pleased to be extending our relationship with BT Cellnet. We are confident we will bring fraud losses down even further and keep them there."

Since BT launched prepay mobiles in July 1998, it has seen its customer base grow to more than five million.