London mayor Boris Johnson has said he will refuse to pay a US capital gains tax bill, it has emerged.
The prospective Conservative Parliamentary candidate, who was born in New York and holds a US passport, revealed his dispute with the US Treasury during an American radio phone-in while he was publicising his new book, The Churchill Factor.
His initially unremarked upon claims, made on November 13, came after he was asked about renouncing his US citizenship, which the caller said was "very hard", on National Public Radio.
Mr Johnson said: "I have to confess to you, that you're right, it is a very - it is very hard, but I will say this, the great United States of America does have some pretty tough rules, you know.
"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 the - for capital gains tax on the sale of your first residence which is not taxable in Britain, but they're trying to hit me with some bill, can you believe it?"
Presenter Susan Page then pressed him whether he would pay the bill, to which he said: "I think it's outrageous.
" Well, I'm - no is the answer. Why should I? I haven't lived in the United States for, you know, well, since I was five years old.
"I could but I pay - I pay the lion's share of my tax, I pay my taxes to the full in the United Kingdom where I live and work."
The Internal Revenue Service, the US government agency responsible for tax affairs, states on its website: "If you are a US citizen or resident alien, the rules for filing income, estate, and gift tax returns and paying estimated tax are generally the same whether you are in the United States or abroad.
"Your worldwide income is subject to US income tax, regardless of where you reside."