Bought your flat from the council under Right to Buy? Your lease has a ground rent capped at £10 and a premium that depends mostly on years left. Here is how an extension works, what to budget, and what six London councils publish.
If you bought your flat from a council under the Right to Buy, your freeholder is almost certainly still that council, and your lease has features that set it apart from a private-sector lease. According to the Leasehold Advisory Service (LEASE), a Right to Buy lease must not charge more than £10 a year ground rent for the whole term. The term itself is normally 125 years, counted from when the first lease in the building was granted rather than from the date you bought. A flat bought ten years after the first sale in a block therefore has about 115 years left at purchase. Some councils hold only a head lease, in which case your term is the head lease length less five days.
Because of that £10 ceiling, ex-council leases do not have the doubling or RPI ground rent problems that cause trouble in private blocks, and the ground rent is a very small part of any extension premium. Some councils say most of their leases carry a peppercorn (zero) rent. That makes ex-council flats a predictable case: the premium is driven mainly by how many years remain and by the value of the flat.
You can extend under the Leasehold Reform, Housing and Urban Development Act 1993 provided you hold a long lease (originally granted for more than 21 years). Since 31 January 2025 you no longer need to have owned the flat for two years before you serve a notice. A statutory extension adds 90 years to the unexpired term and reduces the ground rent to a peppercorn.
The premium for an ex-council flat is calculated in exactly the same way as for a private flat: capitalised ground rent, the value of the freeholder’s reversion, and marriage value once 80 years or fewer remain. With a ground rent of £10 the first element is negligible. The table uses the same maths as our lease extension calculator (5% deferment rate and Gerald Eve 2016 relativity), with £10 ground rent.
| Years left | £250,000 flat | £350,000 flat | £450,000 flat |
|---|---|---|---|
| 60 years | £32,051 | £44,834 | £57,616 |
| 70 years | £21,120 | £29,530 | £37,939 |
| 75 years | £16,560 | £23,145 | £29,730 |
| 80 years | £12,586 | £17,582 | £22,577 |
| 85 years | £4,100 | £5,662 | £7,223 |
Estimates only, before fees. The jump between 80 and 85 years is the point at which marriage value stops applying.
To see where the money goes, take a £350,000 flat with 70 years left. The capitalised ground rent is about £193, the reversion about £11,361 and marriage value about £17,976, giving roughly £29,530. Most of the price is marriage value, which is why extending before the lease falls to 80 years can save thousands. Our 80-year rule guide explains the cliff.
A council extension has two sets of costs in addition to the premium: your own and the council’s. Under section 60 of the 1993 Act you generally pay the freeholder’s reasonable valuation and legal costs as well as your own, whether or not the extension completes once a notice is served. A realistic budget therefore has these lines:
Our solicitor fees guide gives typical ranges for your side of the bill. For the council’s side, check the published schedule for your borough, as they differ.
We checked the leaseholder pages of six London councils on 25 October 2026. Four publish enough detail to summarise, and we have set out what each says. Fees change, so use these as a guide and confirm them with the council before you apply.
| Council | Route offered | Published costs and notes |
|---|---|---|
| Southwark | Formal (statutory) and informal (voluntary) | Council legal fees: £874.50 + VAT fixed for the voluntary route, £307.74 + VAT an hour for the statutory route. £399 non-refundable administration fee. £1,300 valuation fee paid by the leaseholder. Fees are payable at each stage whether or not the extension completes. |
| Wandsworth | Statutory only (1993 Act) | £1,000 valuation costs payable on application and £1,500 legal costs payable if the application is agreed. Premium and legal costs paid on completion. Says most of its leases have a peppercorn ground rent. |
| Tower Hamlets | Formal section 42 notice only; will not negotiate informally | You repay the council’s costs of valuation, negotiation and granting the new lease. No amounts published; costs are set once a formal request is served. |
| Camden | Does not offer voluntary extensions or quote prices | You appoint a solicitor and valuer to serve a section 42 notice proposing a price. Council fees not published on the page we checked. |
| Lambeth | Check the council’s leaseholder pages | We could not verify a published process or fee schedule, so we have not stated one. |
| Westminster | Check the council’s leaseholder pages | We could not verify a published process or fee schedule, so we have not stated one. |
The statutory (formal) route starts when you serve a section 42 notice proposing a premium. The council must respond with a counter-notice, and if the premium is not agreed either side can apply to the First-tier Tribunal. It has fixed timetables, you control the valuation date, and the new lease is on the statutory terms. Some councils, such as Southwark, also offer an informal route with a fixed legal fee. Others, including Tower Hamlets and Camden, accept only formal notices.
An informal deal can be quicker and cheaper in legal costs, but the council is not obliged to follow the statutory formula, the valuation date moves with the negotiation, and you lose the section 42 protections if talks drag on. If you are close to the 80-year line, serving the notice first fixes the valuation date. Our section 42 notice guide sets out the steps.
LEASE says a Right to Buy lease must not charge more than £10 a year for the whole term. Some councils say most of their leases have a peppercorn (zero) rent. After a statutory extension the ground rent becomes a peppercorn.
Yes, if you hold a long lease you can serve a section 42 notice under the 1993 Act. Since 31 January 2025 you do not need to have owned the flat for two years. The extension adds 90 years to the unexpired term.
The premium follows the same statutory method as private flats, so it depends on the years left and the flat’s value. With £10 ground rent, a £350,000 flat with 70 years left comes to roughly £29,500 before fees. Add your own valuer and solicitor and the council’s costs.
It depends on the council. Southwark offers an informal route with a fixed legal fee, while Tower Hamlets and Camden accept only formal section 42 notices. Check your borough’s leaseholder page before you apply.
No. Under section 60 of the 1993 Act you generally pay the freeholder’s reasonable valuation and legal costs as well as your own, once a notice is served.
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This guide is researched from official and primary sources. Check them directly before relying on any figure or date.
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