If you have a residential mortgage and want to let your property, you must get permission from your lender. Renting out a property on a residential mortgage without consent is a breach of your mortgage contract and could lead to the lender demanding immediate full repayment.\n\nWhat Is Consent to Let — A formal agreement from your residential mortgage lender allowing you to rent out the property temporarily. It is not a buy-to-let mortgage. The underlying product remains residential, but the lender acknowledges the change of use. Consent is typically granted for 12 months at a time and must be renewed.\n\nWhen It Is Used — You are relocating for work temporarily and intend to return. You are moving in with a partner but want to keep your property. You have been posted overseas for a fixed period. You cannot sell in the current market and need to move. These are the scenarios lenders understand and generally accommodate.\n\nHow to Apply — Contact your lender's existing customer team and explain the circumstances. Most lenders have a standard consent to let application process. They will want to know why you are letting, the expected duration, the rental income, and whether you have a letting agent. Some lenders charge a one-off fee (typically 75 to 150 pounds) and may add a small interest rate loading (0.25% to 0.5%) to your existing rate.\n\nLender Attitudes — Halifax, Nationwide, Barclays, NatWest, and Santander all grant consent to let in appropriate circumstances. Some lenders are more generous than others in the length of consent granted. A few smaller lenders or older mortgage products may not allow it at all. Building societies vary — some are flexible, others require you to remortgage to a BTL product.\n\nTax and Legal Implications — Even with consent to let, you must declare the rental income on your self-assessment tax return. Section 24 mortgage interest restrictions apply to individual landlords. You need landlord buildings insurance (standard residential cover is invalidated). You must protect the tenant's deposit in a government scheme. You need an EPC rated E or above, a gas safety certificate, and an EICR. Right-to-rent immigration checks apply.\n\nWhen to Switch to BTL — If the letting becomes permanent rather than temporary, most lenders expect you to remortgage onto a proper buy-to-let product. If your lender revokes consent, you must either move back in, remortgage to BTL, or sell. A BTL mortgage is assessed on rental income rather than personal income, and the product terms differ from residential lending.\n\nCommon Mistakes — Renting out without telling your lender (contract breach). Failing to switch insurance to landlord cover (claims will be rejected). Not declaring rental income to HMRC (tax evasion). Forgetting deposit protection (you cannot serve valid notices). Assuming consent lasts indefinitely (it must be renewed).