Most people know Experian, Equifax and TransUnion by name, but far fewer know exactly what data these credit reference agencies (CRAs) actually hold, or where it comes from. Understanding the raw ingredients of your credit file makes it much easier to understand — and improve — the score built on top of it.
Where the data actually comes from
None of the three CRAs generate data themselves — they collect and compile it from external sources. The main contributors are: lenders and credit providers (banks, credit card issuers, loan companies), who report account activity monthly; the Electoral Register, for identity and address verification; the Registry Trust, for County Court Judgments (CCJs) in England and Wales; the Insolvency Service, for bankruptcies and Individual Voluntary Arrangements; and, increasingly, utility and telecoms providers reporting payment history for accounts such as mobile contracts and, via opt-in schemes, rent and household bills.
What a typical UK credit file contains
- Personal details — name, date of birth, current and previous addresses (typically going back 6 years)
- Electoral roll status — whether you're registered to vote at your current address
- Credit accounts — credit cards, loans, mortgages, overdrafts, mobile phone contracts and some retail finance agreements, including opening date, credit limit or loan amount, current balance and monthly payment history
- Public record information — CCJs, bankruptcies, IVAs and Debt Relief Orders
- Search history — a record of who has looked at your file and when, split between soft and hard searches
- Financial associations — links created by joint accounts, joint mortgages or joint applications with other people
- Notices of Correction — a short statement you can add explaining a disputed or unusual entry
Why the three files aren't identical
Not every lender reports to all three agencies — many report to two, and a smaller number report to only one. This means a credit card you opened five years ago might appear clearly on your Experian file but be absent or incomplete on your TransUnion file, simply because that particular lender doesn't have a reporting relationship with TransUnion. See our companion guide on why your credit score differs across platforms for how this affects the headline numbers you see.
What each agency does NOT hold
How to actually access this data
Every UK adult is entitled to a free statutory credit report from each of the three agencies. This is the fullest, rawest version of the data described above — more detailed in places than the simplified summary shown in many free score apps, which is why it's worth checking directly with each CRA at least occasionally, not only via a third-party app.
How long different data types are kept
| Data type | Typical retention |
|---|---|
| Address history | Around 6 years |
| Account payment history | Up to 6 years per entry |
| CCJs, defaults, bankruptcy | 6 years from the relevant date |
| Search history | Up to 12 months (hard searches) |
For a full breakdown of retention periods, see our guide on how long things stay on your credit file.
Why this matters practically
Because the underlying data — not just the headline score — is what lenders ultimately draw on, checking the raw report periodically (rather than only a summary score) is the most reliable way to spot an error, an unrecognised account, or an out-of-date address before it affects a real application.
The bottom line
Your UK credit file is a compiled record built from lenders, public registers and the electoral roll — not a single unified database, and not something any CRA invents on its own. Requesting your free statutory report from Experian, Equifax and TransUnion at least occasionally gives you the clearest possible picture of exactly what lenders can see.