Lenders do not all use the same credit scoring model, and the number Experian or Equifax shows you is not actually what your mortgage lender sees. They run their own proprietary scoring. Still, the underlying data is the same, so improving your credit file with the main agencies helps across the board.\n\nCheck All Three Agencies — Experian, Equifax, and TransUnion each hold slightly different data. A default might appear on one but not another, or an old address could be wrong on just one file. Check all three. You can get free statutory reports from each agency, or use services like ClearScore (Equifax), Credit Karma (TransUnion), and Experian's free membership.\n\nThe Electoral Roll — This is the single easiest win. If you are not registered to vote at your current address, many lenders will decline you automatically. Register at gov.uk/register-to-vote. It takes five minutes and appears on your credit file within weeks.\n\nCredit Utilisation — Keep your credit card balances below 25% of their limits. A card with a 5,000 pound limit and a 4,800 balance looks far worse than the same card at 1,000. If you can, pay down cards before applying. Some people spread their spending across multiple cards to keep each one below 25%.\n\nFinancial Associations — If you have a joint account or joint credit product with someone who has poor credit, their history affects yours through a financial association. If the relationship has ended, contact each credit agency to request a notice of disassociation. This removes the link within a few weeks.\n\nOld Debts and Defaults — Defaults drop off your credit file after six years from the date they were registered, not from the date you paid them. Paying off an old default does not remove it, though it does show as satisfied rather than outstanding. Some lenders view a satisfied default much more favourably than an outstanding one.\n\nStop Applying — Every credit application leaves a hard search footprint visible to other lenders. Multiple searches in a short period suggest desperation. In the six months before your mortgage application, avoid applying for new credit cards, car finance, phone contracts on credit, or buy-now-pay-later services like Klarna, which now appear on credit files.