Subletting and assignment are legally distinct but often confused. Subletting is where the original tenant remains on the tenancy but lets part or all of the property to another person — the original tenant is both your tenant and the subtenant's landlord. Assignment is where the original tenant transfers the whole tenancy to a new person who becomes your direct tenant.
Both arrangements require your consent unless the tenancy agreement or law says otherwise. The Renters' Rights Act 2025 has changed the rules on assignment significantly from 1 May 2026 — landlords in England must now have a permitted reason to refuse assignment of a Periodic Assured Tenancy.
When can a tenant sublet?
Tenants have no automatic right to sublet a residential property in England. The position depends on the tenancy agreement:
- If the tenancy agreement expressly prohibits subletting without consent — the tenant cannot sublet without your written permission
- If the tenancy agreement is silent on subletting — common law applies and the tenant may technically be able to sublet, but this is rare in modern well-drafted agreements
- You may grant consent to sublet on conditions (e.g. the subtenant must pass referencing, the original tenant remains liable for the full rent)
- You can refuse consent to sublet on reasonable grounds — there is no obligation to consent
- Subletting without consent when the agreement prohibits it is a breach of tenancy — this supports a Section 8 Ground 12 notice
Assignment under the Renters' Rights Act 2025
From 1 May 2026, tenants in Periodic Assured Tenancies have a new statutory right to apply to assign the tenancy. Landlords cannot unreasonably refuse:
- A tenant may apply in writing to assign the tenancy to a named proposed assignee
- You must respond within a specified period — refusing without a permitted reason is unlawful
- Permitted grounds for refusal include: proposed assignee fails standard referencing checks, right-to-rent failure, or the landlord has served or is about to serve a Section 8 notice
- On valid assignment: the original tenant's liability ends. The new tenant steps into the original tenant's shoes on the same terms
- Draft your tenancy agreement to set out the assignment process clearly — even though the statutory right cannot be wholly excluded, a clear procedure protects both parties
Unauthorised subletting — what to do
If you discover a tenant has sublet without your consent, act methodically:
- Document the evidence — photographs from inspection visits, post addressed to additional names, evidence of additional occupants
- Contact the tenant in writing and ask them to confirm in writing who is living at the property and on what basis
- If subletting is confirmed, serve a written notice requiring the arrangement to end within a specified period (typically 14–28 days)
- If the tenant fails to comply: the breach supports a Section 8 notice on Ground 12 (breach of a term of the tenancy agreement)
- Do not attempt to evict the subtenant directly — the subtenant may have independent rights, and unlawful eviction is a criminal offence
- Seek legal advice if the subletting has created an HMO — you may need to apply for a licence before any enforcement action
Subletting and the HMO threshold — critical risk
Unauthorised subletting can inadvertently push a property over the HMO licensing threshold:
- A property occupied by 5 or more people from 2 or more separate households requires a mandatory HMO licence
- Many councils also operate additional licensing for 3–4 person HMOs
- If a tenant sublets to a friend and the total occupancy exceeds the HMO threshold, you are operating an unlicensed HMO — even if you had no knowledge of the subletting
- Operating an unlicensed HMO is a criminal offence: unlimited fine, rent repayment order for 12 months' rent, banning order
- Your insurance and mortgage may also be void if the occupancy has changed beyond declared levels
- Include an inspection clause in your tenancy agreement and conduct periodic inspections (with 24 hours' notice) to detect occupancy changes early
Drafting your tenancy agreement to prevent subletting
Prevention is better than enforcement. A well-drafted tenancy agreement minimises subletting risk:
- Include a clear prohibition: 'The tenant shall not sublet, assign, or part with possession of the property or any part of it without the prior written consent of the landlord'
- Define 'permitted occupier' — specify that family members or partners who move in must be notified in writing within 7 days
- Include a clause requiring the tenant to notify the landlord of any change in the number of occupants within a specified period
- Include a periodic inspection clause (minimum 24 hours' written notice) — this allows you to detect occupancy changes and unauthorised subletting
- Specify that breach of the no-subletting clause entitles the landlord to seek possession on Ground 12 — making the consequences clear deters casual breaches
Frequently asked questions
Is subletting always illegal for tenants?+
No — subletting is not illegal in itself, but it almost always requires the landlord's written consent under the terms of a standard tenancy agreement. A tenant who sublets without consent is in breach of the tenancy agreement, which is grounds for possession (Section 8, Ground 12) but not a criminal offence by the tenant.
What is the difference between a subtenant and a lodger?+
A subtenant has a separate tenancy agreement with the original tenant — the subtenant pays rent to the original tenant, not the landlord. A lodger occupies a room in the landlord's own home (not a separate let property) and has a licence, not a tenancy. If the original tenant lives at the property and takes in a lodger (an 'occupier sharing facilities'), this may or may not constitute subletting — check your tenancy agreement's definition of permitted occupiers.
Can I refuse to allow assignment under the Renters' Rights Act?+
Yes — but only on permitted grounds. From 1 May 2026, you must have a lawful reason to refuse assignment of a Periodic Assured Tenancy. Permitted grounds include: the proposed assignee fails referencing (income, credit history, right to rent), or you have already served or intend to serve a Section 8 notice. Refusing assignment without a permitted reason is unlawful — the tenant could seek a court order compelling you to consent.
What happens to the subtenant if I evict the original tenant?+
If you obtain a possession order against the original tenant, the subtenant's occupation typically ends with the original tenancy — the subtenant has no independent right to remain in the property as against you (the freeholder/head landlord). However, the process can be complex if the subtenant has been living there for a long time. Seek legal advice before taking possession action where you know there is a subtenant.