How to dispute an account that isn’t yours on your credit file
Spotted an account on your credit file that you’ve never seen before? That’s alarming — but before you assume the worst, it’s probably not fraud. It’s more likely a “mixed file”, where the CRA’s matching system has accidentally merged someone else’s data onto your report.
This happens more often than you’d think, especially with common names or if you’ve shared an address with family. The good news: once the CRA investigates and confirms the mismatch, the fix is usually straightforward.
Key takeaways
- Don’t panic — it’s more likely a mixed file than fraud. They have very different processes.
- Common with similar names, shared addresses, or family members at the same property.
- Provide proof of identity (passport, driving licence) so the CRA can confirm the mismatch.
- Check all three CRAs — the error may only appear on one.
- Success rate is high once the CRA investigates. These disputes tend to go smoothly.
Is it a mixed file or actual fraud?
A mixed file means the CRA’s data-matching system has incorrectly linked another person’s account to your credit file. This typically happens with people who share similar names and addresses, family members at the same property (e.g., father and son with the same name), previous occupants of your address, or data entry errors (transposed digits in date of birth, similar National Insurance numbers).
Identity fraud is when someone has deliberately used your identity to open accounts. If you suspect fraud rather than a data error, see our guide on disputing fraudulent accounts instead.
What you’ll need
Proof of identity: passport, driving licence, or birth certificate. Proof of address: utility bills, council tax bills showing your correct address history. You may also need to provide your date of birth and National Insurance number to help the CRA distinguish you from the other person.
In most cases, you won’t need to prove the account isn’t yours — the CRA and lender can verify this by comparing the account holder’s details (date of birth, middle name, etc.) against yours.
Where to send your dispute
Experian: Submit a dispute through your free account explaining you don’t recognise the account. Phone: 0344 481 8000. Post: PO Box 9000, Nottingham, NG80 7WP.
Equifax: Use the Online Help portal. Select “Financial Account information” as the dispute category. Phone: 0800 014 2955.
TransUnion: Use transunionstatreport.co.uk — click “Something not right?” on the unrecognised account. Phone: 0330 024 7574.
Here’s exactly what to do
Don’t ignore it — even if it’s clearly not yours, it will affect your score.
Check all three CRAs for the same error.
Contact the CRA and report it as a potential mixed file.
Provide identity documents as requested.
The CRA contacts the lender to verify the account holder’s details.
Once confirmed as a mismatch, the data is removed from your file.
If unresolved, complain to the ICO — this is a data protection issue (inaccurate personal data under UK GDPR).
Evidence checklist
- Proof of identity (passport, driving licence, birth certificate)
- Proof of address (utility bills, council tax)
- Your date of birth and National Insurance number (to help distinguish you)
Dispute this with your CRA
Each agency has a different process. Pick yours for a step-by-step guide:
FAQs
Should I report this to Action Fraud?
Not if it’s a mixed file. A mixed file is a data error, not a crime — Action Fraud won’t investigate it. Only report to Action Fraud if you genuinely believe someone has used your identity to open accounts.
Can this happen even if I’ve never shared an address with anyone?
Yes, though it’s less common. Data entry errors — transposed digits in dates of birth, similar National Insurance numbers — can cause mismatches even without shared addresses.
How long does a mixed file take to fix?
Usually 2–4 weeks once the CRA investigates. They contact the lender, confirm the mismatch, and remove the data. The outcome is almost always in your favour — it’s just a matter of how quickly they get to it.
Related topics
What to read next
How to dispute fraudulent accounts on your credit file
How to remove fraudulent accounts from your UK credit report. Action Fraud reporting, CIFAS Protective Registration, and CRA disputes.
How to fix wrong address information on your credit file
How to fix wrong addresses, name spellings, and personal details on your UK credit report. Avoid mixed files and score damage.
How to dispute an unauthorised hard search on your credit file
Guide to removing unauthorised hard credit searches from your UK credit report. Understand soft vs hard searches, evidence needed, and how to dispute.
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