Since 1 May 2026 nobody in London has a fixed term any more, and that has one consequence most sharers have not yet worked through: on a joint tenancy, a single housemate's notice to quit ends the tenancy for everybody in the flat. Not their room. Not their share. The whole thing, on the date the notice expires. The law firm Russell-Cooke flagged this as one of the Renters' Rights Act's unforeseen effects on joint tenants, noting that the remaining sharers then have to negotiate a fresh agreement with a landlord who has no obligation to offer one and is free to propose a higher rent without going through the statutory increase procedure. So the first rule of replacing a flatmate is simple: the leaver does not touch a notice to quit until the swap is agreed in writing.
What actually changed on 1 May 2026
Phase one of the Renters' Rights Act 2025 came into force on 1 May. Assured shorthold tenancies ceased to exist, every existing fixed term converted automatically into a monthly assured periodic tenancy, and no new fixed terms can be granted. Section 21 went with them, with 31 July 2026 as the deadline for starting court proceedings on any Section 21 served before the switchover.
Tenants gained a two-month notice right from day one of a tenancy, which can be shortened by agreement but not lengthened. The notice has to expire at the end of a rent period: if rent falls due on the 5th, the notice ends on the 4th, not the 5th.
That right belongs to each joint tenant individually, and the common law position (Hammersmith and Fulham v Monk, unchanged by the Act) is that one tenant's valid notice terminates the joint tenancy for all of them. Russell-Cooke points out that around 44% of tenancies were already being ended by tenant notice before the reforms, so this is not a rare edge case. Some agents are now inserting clauses requiring all joint tenants to serve notice together. Treat those with suspicion: the same firm doubts they are enforceable, and a clause that traps you in a tenancy you cannot leave is worse than the problem it solves.
The three ways to swap a sharer
| Route | What happens legally | Effect on rent | Deposit |
|---|---|---|---|
| Assignment | The leaver transfers their interest in the existing tenancy to the incoming sharer by deed. The tenancy itself survives, with its original start date. | Unchanged. The landlord still needs a Section 13 notice to raise it. | Stays protected under the same tenancy. Scheme records and prescribed information must be updated. |
| Surrender and regrant (novation) | The old tenancy ends by agreement and a brand new tenancy is granted to the remaining sharers plus the newcomer. | Landlord can set a new rent at the point of grant. This is the risk. | New tenancy, so protection and prescribed information must be redone within 30 days. |
| Landlord consent without paperwork | The agent says "fine, just tell us who's moving in" and nothing is signed. | Unchanged, but nothing is fixed. | Unchanged, and the leaver stays liable. |
Assignment
This is the one to ask for, and most agents will not offer it unprompted. Because the tenancy continues rather than restarting, the rent stays exactly where it is, the twelve-month clock on rent increases keeps running from its existing date, and your deposit does not need to be re-protected from scratch. Assignment of an assured tenancy needs the landlord's consent, so the leverage question below matters.
Ask for it in writing, in these terms: "We'd like to deal with the change of sharer by deed of assignment rather than a new tenancy, so the existing agreement continues on the same terms. Please confirm the landlord consents and send the deed for signature."
Surrender and regrant
The cleaner option from a landlord's point of view, and the one agents default to, because it lets them reprice. Everything resets: new written statement of terms, new deposit protection, new prescribed information.
It is not all downside. A new tenancy restarts the twelve-month protection during which the landlord cannot use Ground 1A (sale) to recover possession, and it gives you a fresh document in which to fix anything the old one got wrong. If you go this route, get the rent figure agreed in writing before anyone signs anything or serves anything.
The handshake version
Someone moves out, someone moves in, no deed and no new agreement. The leaver remains a joint tenant, jointly and severally liable for rent and damage, and still holds the power to end the tenancy for everyone with two months' notice. The newcomer has no tenancy at all and no claim on the deposit. Every sharer in that flat should refuse this arrangement.
The deposit paperwork nobody checks
If the swap creates a new tenancy, the deposit must be protected again and the prescribed information served again, normally within 30 days of the landlord receiving it, as Shelter's legal guidance on prescribed information sets out. Failure to do that is not a technicality: it exposes the landlord to a compensation claim and to problems with future possession proceedings.
Three things to check the week the swap happens:
- The names. mydeposits' guidance for landlords is clear that the scheme must be told the name of every tenant on the agreement, and that where a lead tenant is nominated, all tenants must agree to that person. Ask for a copy of the updated protection certificate showing your name and the newcomer's.
- The prescribed information. Under scheme guidance, the paperwork should be reissued when the lead tenant changes or where a deed of assignment has been done and the scheme has been notified. Ask for it by name, not as "the deposit stuff".
- The amount. The Tenant Fees Act 2019 caps deposits at five weeks' rent where annual rent is under £50,000, and six weeks at or above it. A changeover is not an opportunity to top the deposit up beyond that.
On fees: the GOV.UK statutory guidance for the Tenant Fees Act says a landlord or agent can charge up to £50 for the administration involved in a change of sharer, or their reasonable costs if higher, and that the general expectation is the charge should not exceed £50. Anything above that must be evidenced. An agent quoting £250 for a "sharer swap admin fee" is quoting a prohibited payment unless they can produce the receipts, and you should say so in writing.
How much leverage you actually have
More than the average WhatsApp group thinks. Foxtons' 2026 lettings reports, drawn from its own London data, show new listings up around 4% year on year with new renters per instruction down 9% year on year, which the agency itself attributes to improved supply and reduced competition between renters. Average achieved rent in those reports sat around £571 a week and was flat year on year. That follows the pattern set in 2025, when Foxtons recorded almost 45,000 new London listings in a single month in June, the strongest supply in four years.
The official data points the same way. The ONS Price Index of Private Rents, in its August 2026 release, put UK average private rent at £1,393 a month in July 2026, up 3.7% over the year. London has been at the bottom of the English table for months: the July 2026 release recorded London rent inflation of 2.2% in the twelve months to June, the lowest of any English region, after 2.0% in the years to April and May. Levels are still eye-watering (the December 2025 release had the London average at £2,271 a month, and Kensington and Chelsea at £3,629 was the most expensive local authority in the country on September 2025 data), but the direction of travel gives a sitting group of tenants a real argument.
Say it out loud to the agent. A landlord facing a void, a fresh referencing round and a marketing spend to replace three tenants instead of one is being offered a costless continuation. That is worth a deed of assignment.
Stopping the swap becoming a rent rise
Since 1 May, Section 13 is the only lawful way to raise rent on an assured periodic tenancy. Rent review clauses in existing agreements became void on that date, increases are limited to once every twelve months, and the landlord must give at least two months' notice on prescribed Form 4A. Informal increases agreed outside Section 13 are not enforceable.
This is exactly why some landlords will insist on a new tenancy at changeover: a regrant lets them set a new rent without any of that. If you are pushed towards a regrant at a higher figure, three moves are available.
- Counter with assignment, on the same terms, and put the void and re-letting cost in the email.
- Agree the regrant only at the existing rent, with the figure confirmed in writing before the incoming sharer signs.
- If they serve a Form 4A later, challenge it at the First-tier Tribunal (Property Chamber). The application is free, and the Renters' Rights Act removed the old deterrent: the tribunal now determines the lower of the open market rent and the landlord's proposed figure, so you cannot end up worse off. Under the previous rules, an analysis by LonRes of 200 published market rent determinations found the tribunal went above the proposed rent in 9% of decisions. That risk is gone.
The same LonRes analysis, published in August 2026, found a median of 96 days from application to decision, and 142 days for London cases. Budget for the wait, and gather your evidence properly: LonRes found that in almost half the decisions giving reasons, the evidence put before the tribunal was thin or one-sided. Screenshots of genuinely comparable current listings on your street, with dates, beat assertions. If you have been paying by app or open banking, your payment history is easy to export as proof of a clean record, which is worth reading up on in our piece on how rent payment apps and open banking are rewriting London renting.
When an individual room contract is the safer bet
If your household changes composition more than once a year, a joint tenancy is now a standing liability. Every sharer holds a switch that ends everyone's home, and every departure needs the landlord's cooperation.
Room-only contracts in a licensed HMO work differently: each person signs their own tenancy of their own room with shared use of the kitchen and bathroom, so one person leaving ends only their agreement. The landlord finds the replacement, which is the trade-off. You lose the veto over who moves in, and per-head rent is often higher than the equivalent share of a whole-flat let.
Take the room contract if the group is loose, if people are on short work contracts, or if one sharer's job is likely to move cities. Keep the joint tenancy if the group is stable, you want control of the spare room, and you value a rent that only moves once a year through Section 13. If you are choosing the area as well as the contract, our rundown of the top areas for young professionals is a reasonable starting point for where room-only stock is thickest.
One last practical sequence, in order: agree the replacement with your housemates, get the landlord's written consent to an assignment or a regrant at an unchanged rent, sign the deed or the new agreement, confirm the deposit protection and prescribed information, and only then let the leaver hand over their keys. The notice to quit should never enter the picture at all.