While often used interchangeably, identity theft and identity fraud are legally distinct terms in the UK.
Identity Theft
Identity theft is the act of acquiring someone else's personal information (e.g., stealing a passport or intercepting mail).
Identity Fraud
Identity fraud is the actual use of that stolen information for financial gain (e.g., opening a credit card in the victim's name).
Why the Distinction Matters
Banks will often only refund money if actual fraud has occurred. If your identity has merely been stolen but not yet used, your priority should be protective registration with CIFAS.