Dame Judi Dench has called for greater protections for London’s parks and green spaces, as research finds more than 50 of the city’s parks are at risk from development.

The Oscar-winning actor has long loved trees, and in 2017 fronted a BBC documentary about her love for them. She plants a tree every time a close friend or relative dies, including for her late husband, Michael Williams, who died in 2001, and the actor Natasha Richardson, who was killed in a skiing accident in 2009, and one for her brother Jeffery Dench, who died in 2014.

She has said: “I think of my trees as part of my extended family. It’s something living that goes on. You don’t remember them and stop; you remember them and the memory goes on and gets more wonderful.”

New research by CPRE London has found that at least nine parks, eight playing fields and eight nature reserves in London are at risk, including Whitewebbs Park in Enfield, Wimbledon Park, and Green Dale Fields in Southwark. After campaigning by CPRE London and local groups, six green spaces were saved last year, including the pitches at Finsbury leisure centre in Islington, but seven were lost, including Crossness nature reserve in Bexley.

Countryside campaigners have criticised the government for allowing development on the green belt in new plans and setting a “grey belt” policy that categorises some protected land as ripe for housing and infrastructure.

In Enfield, the local council has agreed to lease part of Whitewebbs Park to Tottenham Hotspur football club. It is also the site of an ancient oak that was felled by contractors last year, to public dismay.

Dench said: “Staggeringly, 10% of public land in Britain has been lost since 1979. Whitewebbs Park in Enfield is one of the public parks currently under threat. There, a 450-year-old oak tree was brutally butchered and Spurs’ plans to develop the park involve cutting down 207 trees, including veteran and mature trees, and taking over most of the park for their elite private use.

“It is clear to me that it is more important than ever to protect our parks and green spaces before it’s too late.”

A local campaign group, which Dench supports, has initiated a judicial review to appeal against Enfield council’s decision to lease the land.

There has also been a long-running dispute over plans by the All England Lawn Tennis Club to build a new stadium, 10 private buildings and 38 tennis courts on a previously public area of Wimbledon Park.

Alice Roberts, the head of campaigns at CPRE London, said:“In the past two years, we’ve faced two new challenges. Almost unbelievably, a legal judgment confirmed that councils have unfettered powers to sell parks. Elsewhere, parks are being turned into commercial event spaces. If you think London’s parks are protected, think again.

“Second, the UK government has caved in to lobbying to remove green belt protection, introducing a ‘grey belt’ policy enabling landowners to cash in on protected countryside land they bought cheaply years ago, despite wide-scale availability of brownfield land in London, including a staggering 300,000 homes with planning permission unbuilt.”