Boris Johnson, the British foreign secretary, has proposed a tax on overseas buyers of UK property as part of a post-Brexit solution to the country’s housing crisis. Mr Johnson said one of the biggest challenges faced by young people in the UK was the ability to get on to the housing ladder and cited the tax as one of the “obvious ways” to ease demand in the housing market. He said that any tax on foreign buyers – blamed for the rising price of housing in some parts of London – would not currently apply to current members of the 28-nation bloc, wrote Johnson. “No one would want a tax that discouraged international investment… No one would want to send a signal that the London market was closed. But it would at least be possible to have the argument,” he wrote The foreign secretary outlined his plans in an article for the Daily Telegraph seen by some critics as setting the stage for a potential leadership bid of his party and the country. Mr Johnson was a prominent campaigner for the ‘Leave’ campaign and his intervention comes as Theresa May, the prime minister, prepares to deliver a keynote speech on Brexit on Florence on Friday following fractious early discussions with EU negotiators. His 4,000-word vision of post-Brexit Britain makes no mention of a transition deal, an arrangement that would allow the UK access to the bloc’s free market and customs union beyond the March 2019 departure date. The transition deal is backed by other senior ministers, the financial industry and the main UK business organisations as they prepare for life outside the world’s most powerful trading bloc. Mr Johnson was seen as the front-runner in the 2016 race to take over from former prime minister David Cameron, who quit over the result of the EU referendum. However, Mr Johnson pulled out following the decision of a key ally to quit his campaign and run for the leadership himself. Theresa May won the election but has been politically damaged by her decision to call early national elections in this year, which backfired and meant she had to strike a deal with another party to maintain a majority in parliament. She has vowed to stay in charge, but remains vulnerable to a challenge from within her party as the government embarks on difficult negotiations with European Union officials about the terms of their departure from the bloc. Tom Brake, the opposition Liberal Democrat spokesman for Brexit, said that the article was a bid for leadership. “This is about Boris Johnson promoting himself and promoting a hard Brexit agenda,” he told Sky News. The foreign secretary appeared to respond to the claims that it was a thinly-veiled leadership manifesto. “All behind Theresa for a glorious Brexit,” he tweeted. His comments on house prices appeared aimed at younger people who are finding it increasingly hard to buy property in the UK. About a third of first-time house buyers rely on financial help from their families.