In reply to jkarran:
>So skip or delay step one. Start by calling the lender's fraud prevention team to clear up where you stand.
The loss prevention team, will only be interested in debt to their company. As the OP's phone number (from the caller ID) is the same as the fraudsters, they may even believe that the OP and the fraudster are one and the same. I.e. I take out a loan, spend it, then claim someone else did it in my name.
The loan company wont give out any personal details or even discuss the case due to the Data Protection Act. They will happily take all of your details, just in case it is a fraud and you've committed it.
If you go via the action fraud site, they may be able to tell you if your details have been used elsewhere. If the fraudster has done this to 20 other companies, you don't want to spend your days talking to 20 separate loss investigators. Action fraud will have contact with the credit ref companies, and a path to follow to clean up your details.
If it turns out to be one big mistake, i.e. you friend put the wrong number in error; the police will be happy as they can add it to the 'solved' list and make their stats look better.