University students are urged to be on their guard for fraudsters coaxing them into running up large telephone debts.
The Metropolitan Police said university students had been offered cash incentives to entice them into registering for mobile phone contacts and handing over details to be used by a different company.
It is believed students may have given out significant information about their bank accounts, credit or debit cards and personal circumstances, making them targets for identity fraud.
As students return to their university destinations following the summer break, the National Mobile Phone Crime Unit (NMPCU) has launched an investigation into the scam.
Detective Inspector Louise Shea from NMPCU said: "We understand that this matter will be of considerable concern to the students and family members affected as they will be accruing significant debts. We are committed to ensuring that those engaged in fraudulent activity do not escape justice.
"We urge any students that have been affected by this to come forward to assist the investigation and prevent this happening to anyone else."
For advice on how to protect yourself from fraud, call Action Fraud on 0300 1232040.