Plans for longer property leaseholds on affordable homes of 999 years as standard have been set out by London mayor Sadiq Khan.

The new expectation will apply to shared ownership homes delivered through Mr Khan’s £4 billion affordable homes programme, running from 2021 to 2026.

Shorter leases have an impact on the value of a property, as values tend to depreciate drastically when there are 80 years or less left on the lease.

Earlier in January, the Ministry of Housing, Communities and Local Government unveiled a leasehold shake-up which would give leaseholders the right to extend their lease by 990 years.

The proposals, announced by Housing Secretary Robert Jenrick, were billed as some of the biggest reforms to English property law for 40 years.

A freeholder owns both the property and the land it stands on, while leaseholders only own the property, paying ground rent to the freeholder.

Mr Khan said: “Shared ownership properties can be a helpful first rung on the housing ladder for Londoners. However, too many leaseholders continue to face unfair extra costs that increase stress for themselves and their families.

“Shared owners deserve to feel secure in their home for as long as they live there without the threat of an unreasonably costly and burdensome leasehold extension process hanging over them.”