Green card rules ban American residents from voting or standing in foreign elections, the Liberal Democrats claim as they call for an investigation into whether Rishi Sunak breached US immigration regulations.

The Chancellor has admitted to holding a green card granting him permanent residence in America until October last year, more than a year after moving into Number 11, Downing Street.

He initially obtained the permit while he was working in the US but relinquished it when seeking official guidance ahead of his first official trip as Chancellor. 

Now, Layla Moran, the Lib Dems’ foreign affairs spokeswoman, has written to White House officials urging them to launch an investigation because US Department of State documents says that “running for political office in a foreign country” and “voting in foreign elections” constitutes “evidence indicating abandonment of [US] residence”.

The Foreign Affairs Manual lists numerous ways American immigration services should try to establish whether someone is no longer eligible for a green card because they do not really intend to remain in the US. 

Ms Moran has written to Alejandro Mayorkas, the American Secretary of Homeland Security, asking him to investigate whether Mr Sunak should have held the permit when seeking to become the MP for North Yorkshire in 2015 and then when he took the job as Chancellor.

She writes: “This would appear to be in contravention to US State Department rules, which state that running for political office in a foreign country and being employed by a foreign government indicate abandonment of residence in the United States.”

‘Significant public interest’

The letter, also addressed to Charles Rettig, the US Commissioner of Internal Revenue, points out how Mr Sunak and his wife, Akshata Murty, “continued to file tax returns in the United States while he was in apparent breach of these rules.”

Adding how the “issue has become of significant public interest” in the UK, Mr Moran called on the US officials to let the British public know “what sanctions may be applied” if the Chancellor is found to have broken “either the letter or the spirit” of any green card rules.

The Telegraph has established that those guidelines have remained in place from as far back as November 2015, six months before Mr Sunak won the Tory safe seat of Richmond. It remained unclear last night whether the rules applied before Mr Sunak stood for Parliament. 

However, the single paragraph highlighting how voting in foreign elections and running for political office may suggest “evidence” someone no longer intends to be a permanent US resident is one of many possible exemptions.

The Treasury has insisted that Mr Sunak followed “all laws and rules”, including declaring his green card arrangement to the Cabinet Office in 2018 when he became a Minister.

Some Tory MPs have questioned Mr Sunak’s political judgement over the affair, particularly as a politician who is understood to harbour ambitions to one day enter Number 10.