Most accidental landlords start the same way. A job moves, a relationship changes, a flat will not sell. The property is on a residential mortgage, a tenant is willing, and letting it seems like the sensible thing to do.
It usually is. The step people skip is telling the lender, and the reason to take it seriously is not the one they expect.
Not financial advice. Mortgage terms differ by lender and by product. Ask yours.
What the mortgage actually says
A residential mortgage is priced on the assumption that you live there. Letting it out without permission is a breach of the terms, and the standard consequences are contractual rather than criminal: the lender can require the balance, move you to a different rate, or refuse to renew.
In practice, lenders are usually pragmatic about a genuine change of circumstances. What they dislike is finding out from somewhere other than you.
Consent to let is the permission that fixes it. It is a temporary arrangement: the mortgage stays residential, the lender agrees you may let for a defined period, often a year, sometimes with a fee or a rate adjustment. It suits the person who has moved for work and expects to come back, or who is letting while the market recovers.
A buy-to-let-mortgage" class="border-b border-dotted border-emerald-300/60 font-medium text-emerald-800 hover:border-emerald-500 hover:text-emerald-950" data-glossary-link="buy-to-let-mortgage">buy-to-let mortgage is the product for letting as a plan rather than as an interruption. Different rates, different affordability assessment, usually assessed on the rent rather than your income.
The dividing line is intention and duration. If you cannot see yourself living there again, you are probably in buy-to-let territory even if a lender would grant consent.
The part that costs more than the mortgage
Here is what people underestimate: your buildings insurance almost certainly becomes invalid the moment tenants move in.
A residential policy is written for an owner-occupier. Letting is a change of use, and an insurer told nothing has a clean answer at the point of claim. That is not the lender taking a view on your rate; that is a fire with no cover behind it.
So the order is: tell the lender, get the consent or the right product, and tell the insurer in the same week. What each type of cover actually does is worth understanding separately, because "landlord insurance" is a bundle rather than a product.
The other three people you now have to tell
HMRC. Rental income is taxable and the registration deadline is earlier than the filing one: you have to tell them by 5 October following the tax year in which you had the income. The first return has its own timetable.
The freeholder, if it is a leasehold flat. Many leases restrict letting, some require consent, and a few prohibit it outright. Read the lease rather than assuming, and note that the freeholder usually insures the building anyway.
The council, if the property needs a licence. Selective licensing applies to ordinary single lets in designated areas and varies street by street. Check for the exact address rather than the town.
What being a landlord actually requires
The mortgage question is the one people ask. It is not the one that has deadlines attached.
Letting a property in England means a gas safety record renewed annually and served within 28 days of the check, an EICR at least every five years, an EPC of E or above, the deposit protected inside 30 days with prescribed information served, Right to Rent checks on every adult occupier before the tenancy starts, and a written statement of terms given before the tenancy is entered into.
None of it is difficult. All of it has a date, and the dates are what catch people who let one property by accident and treat it as a favour to themselves rather than as a business.
Doing it properly without it taking over your week
LetCompliance runs the whole let from one login: the advert, applications and viewings, referencing, the signed tenancy, the deposit, the rent and any arrears, inspections and check-out, and your tax figures at the end of the year. Certificate dates sit inside that and chase you rather than the other way round.
It is free for one property, which is most accidental landlords, with a 14-day trial of everything if you end up with more.
Common questions
Do I need permission to rent out my house? From your mortgage lender, yes, if it is a residential mortgage. Letting without it breaches the terms. Lenders are usually reasonable about a genuine change of circumstances, but they want to be told rather than to discover it.
What is consent to let? A lender's permission to let a property on a residential mortgage for a defined period, often around a year, sometimes with a fee or a rate change. It suits a temporary let rather than a plan to become a landlord.
When do I need a buy-to-let mortgage instead? When letting is the intention rather than an interruption. Buy-to-let products are usually assessed on the rental income rather than your salary and are priced differently.
Is my home insurance still valid if I let the property? Generally not. A residential policy is written for an owner-occupier and letting is a change of use. Tell the insurer or arrange landlord cover, because this is the exposure that dwarfs the mortgage question.
What happens if I let without telling the lender? It is a breach of contract rather than a criminal offence. The lender can demand repayment, reprice the loan or refuse to renew. The larger practical risk is being uninsured at the same time.
Do I have to tell HMRC? Yes. Register by 5 October following the tax year in which you received rental income.
2026 UK Landlord Compliance Cheat Sheet
Every Gas Safety, EICR, EPC, deposit and Right to Rent deadline on one printable A4 page. Updated for the Renters’ Rights Act 2025.
- Every UK statutory deadline by document type
- Maximum penalty per breach (HSE, MEES, RtR, deposit)
- What blocks a Section 8 / Form 6A possession claim
- Print-friendly A4 with checkboxes
Frequently asked questions
Do I need my lender permission to rent out my house?
If it is on a residential mortgage, yes. Letting without permission breaches the mortgage terms. The consequences are contractual rather than criminal: the lender can require repayment, reprice the loan or decline to renew. Most lenders are reasonable about a genuine change of circumstances provided you tell them rather than leaving them to find out.
What is consent to let?
A lender permission to let a property that stays on a residential mortgage, usually for a defined period such as a year, sometimes with a fee or a rate adjustment. It suits a temporary let, for example a job move, rather than a plan to become a landlord.
When do I need a buy-to-let mortgage instead?
When letting is the intention rather than an interruption. Buy-to-let products are usually assessed on the expected rental income rather than your salary, and are priced differently. If you cannot see yourself living in the property again, that is generally the product you need.
Is my home insurance still valid if I let the property out?
Usually not, and this is the exposure that matters more than the mortgage. A residential policy is written for an owner-occupier, letting is a change of use, and an insurer that was never told has a clean answer at the point of claim. Tell the insurer or arrange landlord cover in the same week you speak to the lender.
Who else do I have to tell?
HMRC, by 5 October following the tax year in which you received rental income. The freeholder, if it is a leasehold flat, because many leases restrict or prohibit letting. And the council, if the address falls within a selective licensing scheme, which varies street by street rather than by town.