Boris Johnson is refusing to pay a large sum in capital gains tax to US officials after he revealed he is in dispute with American authorities.

The Mayor of London claims that he should not have to pay taxes in America because he has not lived there since early childhood – although he was born in New York and holds a US passport.

While many Britons might sympathise with the Mayor’s point of view, it is unlikely to help him in a long-running dispute he has with the US embassy, who have persistently refused to pay London’s congestion charge.

Mr Johnson argues that American diplomats in Britain are liable for the charge, but successive US ambassadors have argued that it is a tax, and have instructed their staff not to pay, though Transport for London continues to bill them. As a result, embassy staff have run up a bill of more than £7m.

Boris Johnson's defining moments Show all 32 1 /32 Boris Johnson's defining moments Boris Johnson's defining moments 2016 Boris Johnson swings from a bus as Northern Ireland Secretary Theresa Villiers (left), Northern First Minister and DUP leader Arlene Foster and Minister of Enterprise, Trade and Investment Jonathan Bell (second right) look on during a visit to Wrightbus Chassis plant in Antrim PA Boris Johnson's defining moments 2015 Boris Johnson takes down 10-year-old Toki Sekiguchi during a game of Street Rugby with a group of Tokyo children Reuters Boris Johnson's defining moments 2015 Boris Johnson planting flowers at the Royal Botanical Gardens in Kew PA Boris Johnson's defining moments 2015 A commuter gesturing to Boris Johnson as he cycles across Vauxhall Bridge PA Boris Johnson's defining moments 2014 Mayor of London Boris Johnson boxes with a trainer during his visit to Fight for Peace Academy in North Woolwich Boris Johnson's defining moments 2014 The Mayor of London Boris Johnson wears a traditional headdress during a visit to the Shree Swaminarayan Mandir, a major new Hindu temple being built in Kingsbury in London Boris Johnson's defining moments 2014 Many Conservative Party members gagging to have Boris Johnson as their MP PA Boris Johnson's defining moments 2014 Boris Johnson prepares to deliver a speech in Bloomberg's European headquarters on Britain's involvement in the EU. Mr Johnson also announced his intention to become an MP again at the 2015 general election, whilst serving out the remainder of his term as mayor. Getty Images Boris Johnson's defining moments 2014 The Mayor of London Boris Johnson during a speech and Q&A session at Bloomberg, London, where he has said that 'in all probability' he will seek to stand for Parliament in next year's general election. PA Wire Boris Johnson's defining moments 2014 London mayor Boris Johnson helps shear a sheep held by New Zealand's most successful competition sheep shearer, David Fagan (L) on a visit to Lister Shearing Equipment in Stonehouse Boris Johnson's defining moments 2013 Mayor of London Boris Johnson takes a helicopter ride over Hong Kong as part of week long visit to China to promote trade between the far east and London PA Boris Johnson's defining moments 2013 Boris Johnson explains why he's such a hit with female voters PA Boris Johnson's defining moments 2013 Boris Johnson celebrates after a wildly successful interview with Eddie Mair PA Boris Johnson's defining moments 2013 Mayor of London Boris Johnson sits in the operator's cab of a crane on the quay at DP World London Gateway Port in Stanford-le-Hope Boris Johnson's defining moments 2013 Boris Johnson shoots a basketball Getty Images Boris Johnson's defining moments 2013 The Mayor of London make a strong pose in what appears to be a particularly bad tourism advert for Asia PA Boris Johnson's defining moments 2013 Boris Johnson meets saltwater crocodile George, which was named after the royal baby EPA Boris Johnson's defining moments 2013 Perhaps the only person ever who has ridden on the Emirates Air Line Getty Images Boris Johnson's defining moments 2012 Boris Johnson's encounter with a zip wire only served to prove how adept the London Mayor is at defying political gravity in 2012 Getty Images Boris Johnson's defining moments 2012 Boris Johnson playing tennis Getty Images Boris Johnson's defining moments 2012 Aside from his mayoral duties, London Mayor, Boris Johnson, is looking displeased at his seven appearances Rex Features Boris Johnson's defining moments 2012 Boris goes for a bounce in one of favourite places... (the Olympic village obviousy) Reuters Boris Johnson's defining moments 2011 London Mayor Boris Johnson on the streets of Clapham REUTERS Boris Johnson's defining moments 2011 Like a raging bull, Boris Johnson challenges a statue to a duel AP Photo/Rajanish Kakade Boris Johnson's defining moments 2010 Boris Johnson embraces a member of the public in Ealing, west London, who seems to have taken a shine to him FACUNDO ARRIZABALAGA Boris Johnson's defining moments 2009 Frothy top? Boris Johnson visits Starbucks in Mayfair PA Boris Johnson's defining moments 2009 Johnson tries on one of his favourite pink and sparkly hats Getty Images Boris Johnson's defining moments 2008 Johnson smiles smugly as he thinks of his fine mop of hair, worthy of a L'Oreal advert PA Boris Johnson's defining moments 2008 Boris Johnson tries his hand at policing the capital - primarily by wearing a new hat PA Boris Johnson's defining moments 2008 The hippie world welcomes a new member to the fold in Boris Johnson Reuters Boris Johnson's defining moments 2004 Boris Johnson jogs on the streets of London PA Boris Johnson's defining moments 1980's Boris as a young'un. He was fired from his first job as a trainee reporter at The Times for making up a quote about the Plantagenet King Edward the II and his gay lover BBC

Mr Johnson has been caught by a rule that says all US citizens abroad, except the lowest paid, are liable for US taxes. His mayoral salary alone would be enough to put him in debt to the US Treasury, even without the larger amounts he earns from journalism. The way out for the Mayor could be to renounce his US citizenship, but he has complained that it not as easy as it sounds.

He revealed his dilemma during an interview on National Public Radio, in the US, after a listener said it was “very hard” to renounce US citizenship, and asked whether London’s Mayor had done so.

Mr Johnson, who was in the US promoting his new biography of Winston Churchill, replied: “It is very hard… You may not believe this but if you’re an American citizen, America exercises this incredible doctrine of global taxation, so that even though tax rates in the UK are far higher and I’m Mayor of London, I pay all my tax in the UK and so I pay a much higher proportion of my income in tax than I would if I lived in America. The United States comes after me, would you believe it, for capital gains tax on the sale of your first residence which is not taxable in Britain. They’re trying to hit me with some bill, can you believe it?”

US citizens abroad also have to pay income tax if their income is above a certain amount (Getty)

The Mayor was asked by the interviewer, Susan Page, whether he was going to pay, and at first tried to avoid answering by saying that the demand was “outrageous”.

Asked again, he replied: “Well, no, is the answer. I think it’s absolutely outrageous. Why should I?... You know, I haven’t lived in the United States since I was five years old.”

Asked whether he would have to renounce his US citizenship if he became Prime Minister, the Mayor replied: “I think the chances of that happening are vanishingly small… That’s what we call a luxury problem to deal with. I think it unlikely to eventuate.”

US citizens abroad also have to pay income tax if their income is above the current cut-off point of $97,600 (£62,000) per year. Mr Johnson’s salary as mayor is £144,000 and he is paid £250,000 for the column he contributes to The Daily Telegraph.

Mr Johnson also dismissed all talk of him becoming Prime Minister as “wild speculation” and denied that he had written a book about Churchill because he thought he was his modern equivalent.