Landlord Mortgage and Consent to Let UK 2026 — Complete Guide

Residential mortgage vs buy-to-let mortgage

The two main mortgage types have very different terms and eligibility criteria:

• Residential mortgage: For owner-occupiers living in the property as their main home. Affordability is assessed on personal income. Letting without the lender's consent is a breach of the mortgage conditions — the lender can demand full repayment
• Buy-to-let (BTL) mortgage: For landlords — the property is let to tenants. Affordability is assessed primarily on the rental income (the Interest Coverage Ratio test), not the borrower's personal income
• ICR stress test: Lenders require rental income to cover 125–145% of the monthly mortgage payment at a stress-test interest rate (typically 5–6%). If the rent does not meet the ICR, the borrowing is limited
• Consumer BTL mortgage: A regulated category for accidental landlords — assessed like a residential mortgage under FCA rules. Typically used when the landlord has an emotional or personal connection to the property (e.g. inherited, previously lived in)

Consent to let — for residential mortgage holders

If you have a residential mortgage and want to let the property, you must obtain the lender's written consent before signing a tenancy agreement:

• Apply in writing to your lender before the tenancy begins — not after. Retrospective consent is rarely granted
• Most lenders grant consent for a defined period (typically 12–24 months) at a fee of £50–£200 and may increase the interest rate while the consent is in place
• Explain the reason for letting: temporary relocation, moving in with a partner, working abroad — lenders are more sympathetic to temporary, genuine reasons
• After the consent period expires, you must either renew the consent, switch to a BTL or consumer BTL mortgage, or sell the property
• Keep the consent letter on file alongside your tenancy compliance documents — the lender may audit and request evidence

What happens if you let without consent?

Letting on a residential mortgage without consent is a serious breach:

• The lender can enforce the mortgage and demand immediate repayment of the full outstanding balance — this is a genuine risk, not a theoretical one
• Your insurance policy may also be void — a residential buildings insurance policy typically excludes letting without the insurer's consent
• If you cannot repay, the lender can seek possession of the property through the courts under Ground 2 (mortgage lender possession — mandatory Section 8 ground)
• Consent obtained retrospectively may not protect you from enforcement if the lender discovers the breach independently
• Always act before the tenancy starts — the cost of asking is minimal compared to the risk of a mortgage being called in

Renters' Rights Act impact on buy-to-let mortgages

The abolition of Section 21 has material implications for BTL mortgage lending:

• Section 21 gave lenders a quick recovery mechanism for properties with non-paying tenants — 2 months' notice, accelerated court procedure, possession order without a full hearing. That route is gone
• Section 8 possession now takes 4–8 months from first missed payment to eviction — during which time the borrower may not be making mortgage payments
• Many BTL lenders have responded by tightening ICR requirements, increasing stress-test rates, and requiring higher deposits for first-time landlords
• Ground 2 (mortgage lender possession) remains available as a mandatory Section 8 ground — but the 2-month notice period and court hearing still apply
• Rent guarantee insurance is now a key risk mitigation tool for mortgaged landlords — it covers rental income during Section 8 proceedings and reduces the lender's indirect exposure

Limited company buy-to-let

Many landlords use a limited company (SPV) for BTL investment — Section 24 tax changes made this more attractive for higher-rate taxpayers:

• A Special Purpose Vehicle (SPV) company with a standard SIC code for residential property rental (68100 or 68209) is the typical structure
• Mortgage interest is fully deductible as a business expense in a company — unlike for individual landlords, where Section 24 restricts mortgage interest relief to the basic rate
• Company BTL mortgages typically carry higher interest rates than personal BTL — the tax saving must exceed the additional finance cost for the structure to be efficient
• The Renters' Rights Act applies regardless of corporate structure — a company-owned BTL property must comply with all the same compliance obligations as an individually owned one
• Take specialist tax advice before incorporating an existing property portfolio — SDLT and CGT on the transfer can be significant

Frequently asked questions