Updated 19/11/2025

If you’re buying or remortgaging in London, the mortgage rules, affordability tests, and lender criteria in 2025 can feel overwhelming. As specialist London mortgage brokers, Trinity Financial helps borrowers navigate complex income, high-value properties, buy-to-let investments, and competitive housing conditions.

This guide explains exactly how to get a mortgage in London, how much you can borrow, and how to improve your chances of approval.

Mortgage lenders have been lowering their two, three and five-year fixed rates in recent months, and another Bank of England base rate cut before Christmas seems likely. Mortgage rates currently start from 3.55% which is very competitively priced. 

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What You’ll Learn in This Guide

• How much deposit you need to buy in London

• Current London income multiples

• How lenders assess your income (salary, bonus, self-employed, contractor)

• The documents required in 2025

• First-time buyer, remortgage, and buy-to-let rules

• Why using a London mortgage broker increases your approval chances

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1. How Much Can You Borrow in London?

Affordability is the biggest challenge for London borrowers. Lender income multiples in 2025 are:

• 4.49× income – standard

• 5– 6x times income and even 6.5× income – select lenders for higher earners, first-time buyers and professionals

• Even higher – case-by-case via specialist lenders

Your borrowing can increase if you have low debts, strong credit, or bonus income. Trinity Financial can compare your affordability across more than 90 lenders to find the most favourable result.

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2. London Deposit Requirements in 2025

Property values in London mean deposits play a major role in mortgage approvals. The average property prices in London have an overall average of £658,016 over the last year, according to Rightmove.

The majority of properties sold in London during the last year were flats, selling for an average price of £535,209. Terraced properties sold for an average of £736,376, with semi-detached properties fetching £757,216.

• 0% mortgages are available
• 5% deposit mortgages are available with multiple lenders

• 10–40% deposit for most purchases

If you’re struggling with deposit size, shared ownership, gifted deposits, or family-assisted mortgage schemes may help.

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3. Documents Needed for a London Mortgage (2025)

Being organised with documents helps reduce application delays.

For employed clients

• 3 months of payslips

• P60

• Recent bank statements

• Photo ID + proof of address

For self-employed clients

• 2 years’ accounts

• SA302s + tax year overviews

• Business bank statements

For contractors

• Current contract

• Day rate calculation

• History of previous contracts

Trinity Financial can review your documents upfront to identify issues before you apply.

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4. How London Mortgage Rates Are Determined

Rates depend on:

• Deposit size (Loan To Value)

• Credit history

• Property type

• Income structure

• Mortgage term

London buyers often benefit from specialist lenders who are not on comparison sites. Trinity Financial has access to many broker-exclusive options.

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5. First-Time Buyer Mortgages in London

London first-time buyers must meet mortgage affordability tests. You can increase your borrowing by:

• Reducing credit card debt and avoiding buying things on credit or taking out loans

• Improving your credit score

• Using lenders who accept 100% of bonus/commission income

• Extending the mortgage term (when appropriate)

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6. Self-Employed, Contractor & Complex Income Mortgages

London’s workforce includes large numbers of self-employed applicants, contractors, and bonus-heavy earners. Lenders treat these differently:

• Some use average income 

• Others accept the latest year if rising

• Some consider retained profits

• Contractor mortgages may use day rate × 48 weeks

Trinity Financial specialises in placing complex income cases with the right lender.

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7. Buy-to-Let Mortgages in London

London yields can be lower than the national average, so lenders rely heavily on rental coverage ratios and stress tests. Requirements are usually:

• 25–40% deposit

• Strong rental income projection

• SPV limited company often preferred

• Portfolio landlord rules apply after 4+ properties

We regularly assist landlords, investors, and SPV companies with London BTL mortgages.

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8. How to Improve Your Mortgage Approval Chances

Here are quick wins that make a big difference:

• Register on the electoral roll

• Reduce credit utilisation below 30%

• Avoid new credit applications

• Keep bank statements clean

• Stay in stable employment during the process

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9. How Long the London Mortgage Process Takes

• Week 1: Consultation + documents

• Week 1–2: Application submission

• Week 2–4: Valuation + underwriting

• Week 4–8: Offer

• Week 8–12: Conveyancing + completion

Trinity Financial can speed this up significantly through pre-application checks.

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10. Why Choose Trinity Financial for Your London Mortgage?

• Access to 90+ lenders, including private banks

• Strong track record with complex income clients

• Expertise in high-value mortgages

• Exclusive & broker-only mortgage rates

• Fast turnaround from enquiry to approval

Call Trinity Financial on 020 7016 0790 to secure a mortgage or book a consultation

Your mortgage is secured on your property. Your property may be repossessed if you do not keep up repayments on your mortgage