Historically ground rent doubled every 25 years on many UK leases. That "doubling clause" trapped owners — banks refused mortgages, properties became unsellable. The 2022 Act capped ground rent at zero ("peppercorn") for new leases.
Existing leases keep their original terms unless renegotiated. The Leasehold and Freehold Reform Act 2024 extends statutory rights to enfranchise (buy the freehold) or extend the lease — most flats now get a 990-year extension at zero ground rent.
If you're buying a leasehold flat, ask for: the current ground rent, the review schedule, when ground rent next escalates, and whether the freeholder has agreed to extinguish the clause.