Mortgages: A UK Borrower's Guide

How a UK mortgage actually works

A mortgage is a long-term loan secured against a property. In the UK, residential mortgages are regulated by the Financial Conduct Authority (FCA) under MCOB rules, which means every lender must run a robust affordability assessment, stress test the borrower against a higher future rate, and lend responsibly. There is no "easy" mortgage in the UK any more — the rules introduced after the Mortgage Market Review (MMR) in 2014 ended that — but there is almost always a lender that will say yes if the case is structured properly.

Three numbers decide most cases: your deposit (which sets the loan-to-value), your income (which sets the borrowing multiple), and your credit profile (which decides which lenders will look at you and at what rate). Everything else — fixed vs tracker, term, repayment vs interest-only, lender brand — is detail layered on top.

Deposit and Loan-to-Value (LTV)

UK mortgages are priced in LTV bands. The lower the LTV, the cheaper the rate. The most common pricing tiers are 60%, 75%, 80%, 85%, 90% and 95% LTV. The biggest single rate cliff usually sits at 85%: drop below it and you typically save 0.4–0.7% on the rate. That means a buyer who can stretch the deposit just a few thousand pounds further can save tens of thousands over a five-year fix.

95% LTV mortgages are available, but the lender list is narrower, rates are materially higher, and criteria around employment and credit are tighter. Government-backed schemes (the Mortgage Guarantee Scheme, Shared Ownership, First Homes) widen the field for buyers with smaller deposits, and our LTV calculator shows which tier you sit in.

Affordability: how lenders really decide

Income multiples are the headline — most UK lenders cap at 4.5× joint income, with some stretching to 5× or even 5.5× for higher earners or certain professions (doctors, lawyers, accountants, vets). But the multiple is only the ceiling. The real test is the lender's affordability calculator, which takes your net income, deducts your monthly credit commitments (loans, credit card minimums, car finance, child maintenance, school fees), applies a stressed mortgage rate of typically 7–8%, and checks that the remaining surplus is enough.

That is why two borrowers with identical incomes can be offered radically different loan amounts depending on their outgoings. Clearing a car loan or a credit card before applying often increases borrowing capacity by £30,000–£60,000. A vetted broker will run your figures through the actual lender calculators rather than guess.

Fixed, tracker, discount and offset — what they mean

• Fixed rate. The interest rate is locked for 2, 3, 5 or 10 years. The default choice for UK borrowers who value certainty. Carries Early Repayment Charges during the fixed period.
• Tracker. The rate moves with the Bank of England base rate plus a fixed margin (e.g. base + 0.69%). Cheaper than a fixed deal when base rate is falling; more expensive when it is rising. Often no ERC.
• Discount. A discount off the lender's Standard Variable Rate (SVR) for a set period. Less common, because SVRs vary by lender and can move independently of base rate.
• Offset. Links a savings account to the mortgage so the balance reduces the interest charged. Powerful for self-employed borrowers and higher-rate taxpayers with material savings; mostly priced at a premium.
• Standard Variable Rate (SVR). The fallback rate when a fixed or tracker deal ends. Almost always the most expensive product the lender sells. Avoid by remortgaging.

Self-employed, contractor and complex income

UK lenders have got much better at lending to self-employed borrowers, but the rules still vary widely. The defaults are two years of accounts or SA302s for sole traders and partners, and two years of company accounts plus salary + dividends for limited company directors. A growing number of lenders will use one year of figures, and a smaller number will use salary plus retained profit (instead of dividends), which can dramatically increase borrowing for owner-managed companies that retain cash in the business.

Contractors are now treated as a distinct category by most lenders. The standard formula is day rate × 5 × 46–48 weeks, used as if it were gross PAYE income, often with no need for accounts at all. This is one of the most under-used routes to higher borrowing for IT, engineering and medical contractors.

The application timeline: DIP to completion

1. Decision in Principle (DIP). A soft credit check and basic affordability ping. Takes minutes; valid 30–90 days; lets you make offers on property.
2. Full application. Submitted after offer accepted. Lender does a hard credit search, requests payslips, bank statements, ID, proof of deposit and property details.
3. Valuation. Lender instructs a surveyor. Most residential valuations are now "desktop" or drive-by; full Level 2 or 3 surveys are buyer-instructed separately.
4. Underwriting. Lender reviews everything, raises queries, and (if happy) issues a mortgage offer. Typically 1–3 weeks from full application.
5. Legal work. Conveyancers handle searches, contracts, exchange and completion. Typical purchase timeline is 10–14 weeks from offer accepted; remortgages 4–8 weeks.

What we cover in this hub

• How UK affordability assessments work after MMR
• Fixed-rate, tracker, discount and offset products in detail
• Deposits, LTV bands and rate tiers
• Self-employed, contractor and limited company director cases
• The application timeline from DIP to completion
• Joint borrower / sole proprietor (JBSP) mortgages and intergenerational lending
• Buying a leasehold flat — cladding, ground rent, EWS1 and what lenders check
• Right to Buy, Shared Ownership and First Homes schemes

Common mortgage mistakes UK buyers make

1. Going to your own bank first. Your bank only knows their own products. A whole-of-market broker sees all 80+ active UK lenders.
2. Applying to multiple lenders simultaneously. Each hard search leaves a footprint; multiple footprints in a short window damages your score.
3. Switching jobs mid-application. Even a promotion can trigger a re-assessment. Time the move for after completion.
4. Hidden credit commitments. Klarna, Clearpay, BNPL accounts and overdrafts all show on credit files now and reduce affordability.
5. Underestimating fees. Arrangement fees, valuation, legals, broker fees, Stamp Duty and surveys add 2–4% on top of the deposit on a typical UK purchase.

Where to go next

Start with the numbers — our repayment, affordability, Stamp Duty and LTV calculators give you a realistic picture in under a minute. If your situation is complex — adverse credit, complex income, buy-to-let, bridging — explore our bad credit mortgages hub or speak directly with a vetted UK broker matched to your scenario.

Your home may be repossessed if you do not keep up repayments on your mortgage. FRN Mortgage Leads is not authorised by the Financial Conduct Authority and does not give regulated mortgage advice. Information on this page is general and educational only.