Form N121 is the particulars of claim form used in possession claims against trespassers. Where the occupiers of a property have no tenancy, licence, or other lawful basis for being there, the legal framework is fundamentally different from possession against tenants. Form N121 — used together with Form N5 — is the procedural vehicle for trespasser claims. Trespasser possession claims are relatively rare in the residential rental context, typically arising with squatters, former tenants whose tenancy has been cleanly determined, or persons given temporary permission whose permission has been revoked. This page covers when Form N121 is used, section-by-section completion, the documents to file, service difficulties (including against persons unknown), the faster procedure, the choice between trespasser and standard possession against former tenants, and the criminal offence of residential squatting under LASPO 2012.
What Form N121 is
Form N121 is the particulars of claim form used in possession claims against trespassers. Where the occupiers of a property have no tenancy, licence, or other lawful basis for being there, the legal framework is fundamentally different from possession against tenants. Form N121 — used together with Form N5 — is the procedural vehicle for trespasser claims.
Trespasser possession claims are relatively rare in the residential rental context. They typically arise in three scenarios:
- Squatters who have entered a property without permission. The Legal Aid, Sentencing and Punishment of Offenders Act 2012 made squatting in residential property a criminal offence, but the criminal route does not always produce timely vacant possession; the civil possession claim remains relevant.
- Former tenants whose tenancy has ended but who remain in occupation as trespassers. Where a tenancy was determined by surrender, expiry of a fixed term (under pre-RRA frameworks), or court order, and the former tenant remains, they become trespassers — though in practice possession against former tenants is usually pursued via the standard possession procedure.
- Persons given temporary permission to occupy whose permission has been revoked but who remain — for example, a guest of a tenant who has stayed beyond the tenant’s permission, or someone occupying under an arrangement that has ended.
The current edition of Form N121 is at gov.uk.
When Form N121 is used
Form N121 is used together with Form N5 (the standard claim form). The combination — Form N5 ticked at “trespass” with Form N121 as the particulars — is the procedural route for trespasser possession claims under Civil Procedure Rules Part 55.
Trespasser possession claims have specific procedural features:
- Faster procedure: trespasser claims can be heard more quickly than tenant possession claims. The CPR provide for shortened time limits in appropriate cases.
- Possession against persons unknown: where the trespassers cannot be identified by name (squatters, for example), the claim can be issued against “persons unknown” with description of the occupied premises.
- Service by alternative methods: where the trespassers cannot be served by usual means, the court can permit service by alternative methods — affixing a notice to the property, for example.
Section-by-section completion
1. Property details
Section 1: full address of the property occupied by the trespassers, including postcode. Where the trespassers occupy only part of a larger property, the specific area should be identified.
2. Claimant details
Section 2: full name and address of the claimant — the property owner or person with a sufficient interest to bring the claim.
3. Defendant details
Section 3: identification of the defendants. Where the trespassers can be identified by name, full names should be given. Where they cannot, the claim is brought against “persons unknown” with a description of the property occupied.
4. Basis for the claim
Section 4: the factual basis for the claim that the defendants are trespassers. Typically:
- The claimant’s legal interest in the property (freehold, leasehold, etc.).
- When and how the defendants entered the property (or commenced their unlawful occupation).
- Whether the defendants ever had any lawful basis for being there (and if so, when and how that basis ended).
- Steps taken to ask the defendants to leave (warnings, requests, formal notices).
5. Grounds for possession
Section 5: the legal grounds on which possession is claimed. For pure trespasser cases, the ground is straightforward — the defendants have no right to occupy the property. Where the basis is more complex (e.g. former tenants whose tenancy has been determined), the determination should be evidenced.
6. Statement of truth
Standard statement of truth signed by the claimant or representative.
Documents to file with Form N121
Together with Form N5 and Form N121:
- Evidence of the claimant’s legal interest in the property (title deeds, lease, or similar).
- Any photographs or other evidence of the trespassers’ occupation.
- Any correspondence with the defendants asking them to leave.
- Any evidence of how the defendants came to be in the property.
- Where possession is sought against persons unknown, evidence of the steps taken to identify the occupiers.
How to file Form N121
Form N121 is filed with Form N5 at the County Court for the area in which the property is located. Court fee: £404 (the standard possession claim fee).
In urgent cases, an application for an interim possession order (IPO) may be available — providing rapid possession ahead of a full hearing. IPOs are governed by separate provisions and have specific procedural requirements; they are typically used only where the trespasser occupation is causing significant ongoing damage or risk.
Service
Service in trespasser claims is often more difficult than in tenant claims. Where the trespassers can be named and contacted, standard service rules apply. Where they cannot:
- The court can authorise service by alternative methods — affixing notice to the property door, leaving copies in prominent locations.
- Where possession is sought against persons unknown, service is typically by physical attachment to the property and posting at prominent points.
- The court can order substituted service (e.g. by social media, where appropriate).
Form N215 (certificate of service) is filed to evidence whatever service was effected. See our N215 guide.
What happens after issue
Trespasser claims typically proceed faster than tenant possession claims:
- The court may abridge the standard time limits.
- A hearing is listed (often 2-4 weeks after issue rather than the standard 8-12).
- The defendants have a shorter time to file any defence.
- At the hearing, the court considers the claim and either grants possession (if the case is established) or directs further evidence.
Possession orders against trespassers typically take effect immediately or with a very short period (3-7 days rather than 14 days). Enforcement is via Form N325 — see our N325 guide.
Trespasser claims vs former tenant possession
Where a former tenant remains in occupation after the tenancy has ended, the choice between treating them as a trespasser (Form N121) or pursuing standard possession can be significant:
- Where the tenancy ended cleanly (e.g. by tenant’s notice or by surrender), the former tenant may technically be a trespasser. Form N121 may be appropriate.
- Where the tenancy ended on the landlord’s notice, the standard possession procedure (Form N5 + Form N119) is typically used. The court treats the former tenant as still a tenant for procedural purposes until possession is obtained.
- Where there is doubt about whether the tenancy ended, the safer course is the standard possession procedure with the appropriate Section 8 grounds.
Where the situation is unclear, legal advice is valuable. Pursuing trespasser possession against someone with arguable tenant rights can produce procedural setbacks.
Squatting in residential property
Squatting in residential property has been a criminal offence under section 144 of the Legal Aid, Sentencing and Punishment of Offenders Act 2012 since 1 September 2012. Penalties include up to 6 months imprisonment, an unlimited fine, or both.
The criminal route can be faster than civil possession in some cases — police can arrest squatters and remove them physically. However, police engagement varies, and many squatter situations are still resolved through civil possession even where the criminal offence is engaged.
Squatting in non-residential property (commercial premises, vacant land) is not within the criminal offence and remains principally a civil matter.