How your UK credit score is built
The three UK credit reference agencies are Experian, Equifax, and TransUnion. Each maintains a file on you and sells it to lenders. There is no single official score, the headline numbers you see on ClearScore, Credit Karma, and Experian are the agency’s own marketing scores. What lenders actually buy is your underlying file: payment history (on time, late, missed), credit utilisation, length of accounts, recent applications, electoral roll status, and any defaults, CCJs, or IVAs from the last six years.
On a £200,000, 25-year fixed mortgage, the gap between a top-tier credit profile getting 4.5% and a marginal profile getting 5.5% is roughly £120 a month extra, or about £36,000 over the term. Getting on the electoral roll, paying every direct debit on time for 12 months, and keeping credit card utilisation under 30% does most of the lifting.
Cancelling your oldest credit card to ‘tidy up’. You shorten your average account age and shrink your total credit limit, which pushes utilisation up on everything else. Keep old, no-fee cards open and use them once a quarter.
A 60-second lesson on this, with a worked drill, lives inside the Finlo app. Free, forever, on the basics.