The mayor of London’s office has taken charge of the decision on whether to approve the All England Lawn Tennis Club’s controversial plans to build on a Grade II*-listed park to expand the Wimbledon grand slam championships. “This is a major planning application, of London-wide significance,” a spokesperson for city hall said on Monday. “Therefore, the deputy mayor has issued a direction under article 7 of the Town and Country Planning (Mayor of London) Order that he becomes the local planning authority for the purposes of determining the application. A full planning hearing will be held in due course.” The AELTC, which has been running the championships since 1877, has applied for permission to build an 8,000-seat, 10-storey show court and 38 other grass courts on Wimbledon Park, but campaigners have condemned the as an “industrial tennis complex”. The proposals to almost triple the size of the tennis championship grounds from 17 hectares (42 acres) to 46 hectares had been approved by Merton council but rejected by neighbouring Wandsworth council. Wimbledon Park, which was landscaped by Capability Brown in the 18th century and is specially protected as “metropolitan open land”, stretches into both boroughs so in order for the plans to go ahead it needed to be approved by both councils. Merton referred the decision to the Greater London Authority (GLA). The decision officially lies with the mayor of London, Sadiq Khan, but he recused himself because he publicly expressed support for the expansion in 2021. The deputy mayor of London, Jules Pipe, made the decision to take control of the application at the mayor’s planning meeting on Monday. More than 16,000 people have signed a petition to “save Wimbledon Park” and 2,000 letters of objection have been received by the councils. The local Conservative MP, Stephen Hammond, and the Labour MP Fleur Anderson have also joined forces to oppose the AELTC’s plans. Anderson, the MP for Putney, Roehampton and Southfields and Wandsworth Town, said: “I have been campaigning against these proposals, alongside residents, for three years. The plans as they currently stand are bad for public access to green space, Londoners’ lungs and our environment. “The GLA is a world-leading local authority when it comes to putting Londoners’ health and our environment first. I hope that they will tell Wimbledon Tennis they need to go back to the drawing board.” Deborah Jevans, the chair of the AELTC, welcomed city hall’s decision to review the application. “Our proposals will deliver one of the greatest sporting transformations for London since the 2012 Olympics,” she said. “It will bring the qualifying event on site, in line with the other grand slams, and will ensure that Wimbledon remains one of the world’s best sporting events.” Jevans said the club’s plans would “unlock year-round community benefits including a new 23-acre park created on land which has been inaccessible to the public for over 100 years”. “Protecting the future of the championships, as well as significantly increasing publicly accessible green space, is a win-win for Londoners and will demonstrate beyond doubt that London is the sporting capital of the world.” Iain Simpson, the chair of the Save Wimbledon Park (SWP) campaign group, also welcomed the announcement. He said: “It is notable that all political parties have declared their opposition to the AELTC’s plans. SWP have been fighting this application since it was made three years ago. We have been urging the AELTC to speak to us, their local communities: it is time for them to think again.” Almost 300 trees would be removed to allow the AELTC’s building plans, which some locals described as “corporate ecocide”. The club said most of the trees were “poor quality” and promised to plant 1,500 new ones. The AELTC first set its sights on expanding into Wimbledon Park in 1993 when it bought the freehold of the land from Merton council for £5.2m. But it signed a covenant agreeing that it would “not use the [land] other than for leisure or recreational purposes or as an open space”. The club rented the land to Wimbledon Park golf club until 2018 when its chair said he feared the SW19 championships would fall behind its competitors in New York, Paris and Melbourne if it did not expand and offer greater facilities for players and spectators. The obvious place to expand, he said, was on to the golf club. However, the golf club’s lease on the land lasted until 2041, so the AELTC could not take back the land for another 23 years. The tennis club offered the golf club members £65m to give up their club early. That worked out as an £85,000 windfall for every member, including Piers Morgan, Ant McPartlin and Declan Donnelly, and Gus O’Donnell, the former cabinet secretary.