Boris Johnson is facing off against Leonardo DiCaprio in a row over Sadiq Khan's decision to target motorists by expanding the London Ultra-low emission zone (Ulez).
In a letter to the Telegraph, the former prime minister and a group of Conservative MPs criticise a “smash and grab raid on drivers" by the London mayor following his decision to expand a low-emission zone across all of Greater London. The charge will mean thousands of drivers will have to pay £12.50 a day because their vehicles do not meet minimum pollution standards.
The intervention pits Mr Johnson against Mr DiCaprio, the star of films such as Titanic, Catch Me if You Can and The Beach.
The Hollywood A-lister took to social media to lavish praise on Mr Khan for expanding Ulez, saying: “[It] will mean five million more people breathing cleaner air, and will help to build a better, greener, fairer London for everyone.
“This is the kind of large-scale, decision action we need to halve emissions this decade, , coupled with the implementation of nature-based solutions."
It is not the first time Mr DiCaprio has backed the Labour London mayor over his ambition to reduce pollution in the capital. In 2019, he praised Mr Khan “for taking the lead on tackling air pollution in London", adding: "Clean air is a human right.”
Mr Khan, whose book "Breathe: Tackling the Climate Emergency", is due to be published in May, was quick to thank Mr DiCaprio, saying it was great to have his support.
Other signatories to the letter objecting to Ulez expansion include Mr Johnson's fellow former Conservative leader Sir Iain Duncan Smith; the former Transport Secretary Chris Grayling; and current minister for London, Paul Scully.
Some 60pc of respondents to a public consultation opposed Mr Khan’s plans to expand Ulez across all of Greater London.
In the letter, which was coordinated by the Orpington MP Gareth Bacon, MPs said Mr Khan’s decision is “undemocratic and a hammer blow to households’ budgets”.
Mr Johnson announced plans to implement the world’s first low emission zone in London in 2015, when he was the capital's mayor. He has since opposed Mr Khan's plan to expand the zone, first to the north and south circular roads and now to within sight of the M25.
The MPs said: “The Ulez was never intended to apply to outer London. This is a smash and grab raid on drivers’ wallets that has nothing to do with air quality and everything to do with Khan’s mismanagement of [Transport for London’s] finances. And it comes at the worst possible time for household income."
Despite insisting that he would not go ahead with Ulez expansion if there was overwhelming opposition to it, Mr Khan told the Telegraph last week: “I didn't call a referendum; this was a consultation.”
He also revealed his intention to roll out a “Singapore-style” network of toll roads across London once drivers have switched to electric vehicles. The London mayor said that road pricing will be introduced to replace the congestion charge and levies for the Ultra-low emission zone (Ulez) that could use a network of cameras across the capital.
Mr Khan reaffirmed his flagship Ulez policy on Thursday as part of Transport for London’s business plan to invest £8.1 billion in London’s road and rail networks.
Improvements to the capital’s public transport system include replacing Piccadilly line trains with a new fleet that would have the capability to be run driverless if the Government signs-off money to upgrade signals and platforms.
Mr Khan, TfL’s chairman, has repeatedly clashed with Westminster over the rollout of driverless Tube trains. Despite pressure from the Government to consider implementing driverless technology, the London mayor has branded such changes as “madness”.
Nevertheless, industry sources told the Telegraph that City Hall officials are regularly in conversation with bosses at the likes of Siemens - which is building the Piccadilly Line trains - about upgrading signalling and erecting screens on platforms to make driverless trains a reality.
Separately, the business plan set aside £150m-a-year until 2026 to be spent on building new cycle lanes.
Meanwhile, officials hinted that TfL could be amenable to the sponsorship of London Underground stations - a core plank of the unsuccessful bid by Conservative mayoral candidate Shaun Bailey last year.
The business plan said: "We are showcasing new and groundbreaking ways of working with brands. This includes innovative brand activations on the Underground, creative collaborations using our globally recognised symbols, and managing the filming of Hollywood blockbusters across the network."