01 · Why it's goneWhat Section 21 was, and why it is being retired
Section 21 of the Housing Act 1988 defined private letting for a generation. Two months' written notice, no reason required, statutory possession after court-ordered bailiff warrant. It was the engine of the assured-shorthold tenancy and the reason landlords were willing to let in the first place.
Under the Renters' Rights Act 2025, Section 21 is repealed. The political argument, made since 2019 and finally enacted in 2025, is that no-fault eviction created tenure insecurity on a scale that distorted the market, tenants afraid to raise disrepair complaints, schools losing pupils mid-year to evictions, and a possession regime that did not require the landlord to show why they wanted their property back.
Whether you agree with the politics or not, the operational reality from commencement is unchanged by the debate. Section 21 goes. In its place, landlords rely exclusively on a strengthened Section 8 with new grounds and a higher evidential bar.
Part of a wider reform
Section 21 abolition is one of five headline provisions in the Renters' Rights Act 2025, alongside the landlord ombudsman, the PRS database, rent-increase caps and the Awaab's Law PRS extension. This piece zooms in on the possession mechanics, the other four provisions are decoded in the mega-article.
02 · The new groundsThe new Section 8 grounds, six that do most of the work
The Section 8 framework was always there; it just wasn't used much, because Section 21 was faster and easier. Under the 2025 Act, Section 8 is the only route, and some grounds have been strengthened while others are new. Six grounds account for roughly 90% of London possession applications.
Ground 8 · Rent arrears
MandatoryStill the most common route. The arrears threshold rises (the exact figure set by the SI, expected around three months for monthly tenancies and eight weeks for weekly), and the landlord must prove the arrears at the court hearing, not just at the point of serving notice. A tenant who clears arrears below the threshold before the hearing can defeat the ground.
Ground 8A · Persistent arrears
MandatoryA tightened version of the discretionary Ground 11 that catches tenants who repeatedly fall into and out of arrears without ever crossing the Ground 8 threshold at a single point in time. Four or five periods of arrears in the preceding 12 months typically satisfies the test. Useful where the Ground 8 threshold keeps getting cleared a week before hearing.
Ground 1A · Landlord sale
NewNew mandatory ground replacing the sale-motivated use of Section 21. The landlord must genuinely intend to sell the property with vacant possession. Court may require evidence (marketing instructions, agent's letter). Once granted, a 12-month re-let prohibition applies, letting the property again within that window is a prescribed Rent Repayment Order offence.
Ground 1B · Landlord / close-family move-in
NewNew mandatory ground covering landlord move-in or move-in by a close family member (spouse, civil partner, parent, child, sibling or their equivalents). The move-in must be genuine and of intended duration, token residence followed by quick re-let will fail. Same 12-month re-let prohibition and RRO consequence as Ground 1A.
Ground 14 · Anti-social behaviour
DiscretionaryStrengthened under the 2025 Act. Conduct that is a nuisance or annoyance to any person in the locality or to the landlord's representative. Requires evidence (police reports, neighbour witness statements, photos, local-authority nuisance notices) and the court weighs reasonableness. Broader than pre-2025, includes serious persistent noise and retaliatory behaviour to neighbours.
Ground 6 · Demolition / reconstruction
MandatoryRetained largely unchanged. Available where the landlord intends to demolish, reconstruct, or carry out works that cannot be performed with the tenant in place. Requires genuine intention, evidence of the planning or permission route, and usually a compensation offer to the tenant. Less common in single-property PRS; more common in block-wide redevelopment.
Other grounds (breach of tenancy, serious disrepair caused by tenant, rent arrears before tenancy started) remain available but are used less often. The Ground 8 + Ground 1A + Ground 1B combination will carry 80%+ of London possession cases post-commencement.
03 · TransitionWhat happens to existing ASTs and live notices
The transition from Section 21 to Section 8 is the part of the Act most likely to catch landlords out. The simplest way to understand it is to separate three cases:
| Your position at commencement | Before commencement | After commencement |
|---|---|---|
| Fixed-term AST with no s.21 served | Standard fixed-term AST; s.21 available at expiry | Converts automatically to a periodic tenancy at commencement. Possession only via Section 8 grounds. |
| s.21 served pre-commencement, not yet expired | Valid s.21; possession claim can proceed | Notice remains valid on its original timetable. Claim made under the pre-commencement regime; court applies the old rules. |
| New tenancy granted after commencement | Would have been fixed-term AST | Periodic from day one. No fixed-term; possession only via Section 8. Fixed-term clauses in the lease will not override. |
Two practical points. First, any s.21 notice you might reasonably want to serve should be served before commencement, the tool disappears on commencement day and there is no path back. Second, the automatic conversion of fixed-term to periodic means tenants gain some flexibility too: a tenant in a 12-month fixed-term AST before commencement can give two months' notice to end the tenancy after commencement, even if that falls inside the original fixed term.
Possession in the first year will take longer
Expect 12–20 weeks to possession under the new regime in the first year of commencement, versus the 8–14 weeks typical under s.21. Courts are working through a backlog, the evidential burden is materially higher, and judges are unfamiliar with the strengthened grounds. Clean rent-ledger and tenancy paperwork are the single biggest determinant of how far your case lands from the top of that range.
The landlords who come through commencement cleanest are the ones who tightened their rent-ledger discipline in the six months beforehand. Not because arrears suddenly matter more, but because Ground 8 is now the most load-bearing ground in the regime, and it is only as strong as the paper trail behind it.
04 · MechanicsPossession mechanics and timelines
Under the new regime, the mechanical sequence from landlord decision to bailiff-led recovery runs something like this:
- Decision and ground selection. Pick the Section 8 ground that matches the facts. Multiple grounds can be pleaded on one notice, but each must be evidenceable.
- Prescribed Section 8 notice. Served on the tenant, specifying the grounds and the earliest date proceedings can start. Notice periods: 2 months for most grounds, 4 months for sale and move-in grounds, longer for tenancies under 12 months.
- Wait period. Notice period expires. Tenant may pay arrears, leave voluntarily, or stay.
- Possession claim issued at county court. If tenant remains, landlord files the N5 / N5A possession claim with supporting evidence. Court issues a hearing listing.
- Hearing. Judge reviews evidence. For mandatory grounds, possession is granted if the ground is made out; for discretionary grounds, the judge also weighs reasonableness.
- Possession order. Usually gives 14 days to leave; can be extended up to 42 days in exceptional circumstances.
- Bailiff warrant. If tenant remains after the possession-order date, landlord applies for a warrant of possession. Bailiff scheduling adds 4–8 weeks in most London county courts.
The single biggest delay variable is the court-hearing lag, which depends on the listing queue at the specific county court. Central London and Clerkenwell & Shoreditch are typically the slowest; Bromley and Romford tend to clear faster.
05 · Worked examplePossession on Ground 1A (sale), timeline
Single-let flat, Islington, landlord wants to sell
A landlord owns a 2-bed flat in Islington N1, let to the same tenant since 2023 on a periodic tenancy (converted from fixed-term at commencement). In October 2026 the landlord decides to sell with vacant possession. No rent arrears; no anti-social behaviour. Only available ground: Ground 1A.
- Week 1. Landlord instructs estate agent and obtains a marketing instruction letter dated to the week of notice service. Keeps written instruction and online listing screenshot as evidence.
- Week 2. Prescribed Section 8 notice served on tenant, citing Ground 1A. Four-month notice period expires Week 18. Statutory declaration prepared naming the intended sale.
- Week 18. Notice expires. Tenant chooses not to leave. Landlord files the N5A possession claim at the county court covering Islington. Filing fee around £400 (2026 figure).
- Week 24. Court issues a hearing listing for Week 30.
- Week 30. Hearing held. Judge reviews the Ground 1A evidence: marketing instruction, listing screenshots, statutory declaration. Satisfied that the intention to sell is genuine. Mandatory possession order granted; 14 days to leave.
- Week 32. Possession order date. Tenant still in occupation. Landlord applies for bailiff's warrant.
- Week 38. Bailiff executes possession. Landlord recovers the flat. Total elapsed time from Week 1 to Week 38: approximately 37 weeks, roughly twice the pre-commencement Section 21 timeline.
- From Week 38 onwards. The 12-month re-let prohibition under Ground 1A runs for 12 months. The property must be genuinely marketed for sale; any re-letting inside that window (even to a new tenant) is a prescribed RRO offence and the tenant can recover up to 12 months' rent.
37 weeks
A defensible year-one estimate for a Ground 1A possession from decision to bailiff recovery, assuming an uncontested hearing. Shorter where the tenant leaves at notice expiry; longer where any evidence challenge is mounted.
06 · ActionWhat to do now, before commencement lands
If commencement is still some months out at the time you are reading this, these are the four things that genuinely move the needle:
- Audit every live AST for latent Section 21 windows. Any s.21 you might reasonably want to serve in the next 6 months should be served now. The tool disappears on commencement day with no transition route back.
- Tighten your rent-ledger discipline. Ground 8 becomes the most load-bearing mandatory ground. Make sure your rent records are clean, signed, time-stamped, and that demand letters are going out promptly when a payment is late.
- Revise your default lease templates. Post-commencement periodic templates, prescribed-information pack aligned to the new statutory framework, updated notice templates for both sale and move-in scenarios.
- Run a portfolio compliance audit. Possession under Ground 8 fails if the landlord has been materially in breach (out-of-date gas certificate, missed EICR, no valid deposit-protection lodgement). Compliance is now part of the possession toolkit. See our For Landlords page for an audit route.
07 · FAQsQuestions landlords keep asking
When is Section 21 abolished?
Section 21 is abolished under the Renters' Rights Act 2025; commencement of the Section 21 replacement provisions is scheduled for Q3 2026 via a separate statutory instrument. The Act itself completed parliamentary stages in late 2025. Until commencement, Section 21 notices can still be served; after commencement, only the strengthened Section 8 grounds are available for possession in the PRS.
What happens to a Section 21 notice I have already served?
A Section 21 notice served and valid before commencement remains valid on its original timetable, the Renters' Rights Act 2025 does not retroactively invalidate pre-commencement notices. You can continue with the possession claim on the original basis, and the court will decide the case under the regime in force when the claim was issued. After commencement, no new Section 21 notices can be served.
What are the new Section 8 grounds landlords can use?
Post-commencement, landlords use a strengthened Section 8 with both retained and new grounds. Key mandatory grounds include rent arrears (Ground 8, with a higher evidential threshold), landlord sale (new Ground 1A), landlord or close family move-in (new Ground 1B), and demolition or reconstruction (Ground 6). Discretionary grounds include persistent rent arrears, anti-social behaviour, breach of tenancy and serious disrepair caused by the tenant.
How long will possession take under the new regime?
Budget 12–20 weeks in the first year of commencement. Notice periods run 2 months for most grounds, 4 months for sale and move-in grounds, longer where the tenancy has run less than 12 months. Add 6–10 weeks for hearing listing and 4–8 weeks for bailiff scheduling where the tenant does not leave voluntarily. Typical time to possession under the pre-commencement Section 21 was 8–14 weeks; the new regime roughly doubles that in year one as courts adjust.
Can I still evict for rent arrears?
Yes, under strengthened Ground 8, but the mandatory threshold rises and the landlord must prove the arrears at the court hearing, not just at the point of serving notice. The persistent-arrears Ground 8A is also strengthened. Rent arrears remains the most reliable possession route, but the paper trail and evidential burden are materially higher than under the pre-commencement Ground 8, and tenants who clear arrears before the hearing can defeat the ground.
What happens to fixed-term tenancies at commencement?
At commencement of the Section 21 replacement provisions, all existing fixed-term ASTs convert automatically to periodic tenancies. New tenancies granted after commencement are periodic from day one. Fixed-term clauses drafted for post-commencement tenancies will not override the statutory position. Tenants gain more flexibility to end the tenancy with two months' notice; landlords must rely on the Section 8 grounds for possession.
Tighten rent ledgers, lease templates and compliance before the tool disappears
One audit, every statutory duty mapped, a fixed-price clean-up plan before commencement lands. See the 17-duty matrix on For Landlords for the scope.
08 · Where to go nextTwo practical follow-ups
If possession and transition is the part of the 2025 Act you are most exposed to, these are the two reads that close the loop.
First, the Renters' Rights Act 2025 complete guide, the 14-minute mega-article covering all five headline provisions of the Act, commencement sequence, and a portfolio-level operational playbook.
Second, subscribe to The HSE compliance briefing. One email a month with regulatory-landscape updates and one actionable thing to do before the next deadline. When the Section 21 commencement SI lands, you will hear it from Kevin within the week.
HSE service for this topic
Pre-commencement portfolio audit · fixed price
Tighten rent ledgers, lease templates, and all 17 statutory duties before the tool disappears. Clean possession evidence is the difference between an 18-week case and a 37-week one.