United States President Donald Trump walked out of the Iran nuclear deal merely to spite his predecessor Barack Obama, Britain’s former Ambassador to Washington, Kim Darroch, wrote in a memo to Downing Street, The Daily Mail reported on Saturday. Darroch’s claim was revealed in leaked cables and briefing notes, which led to him resigning last week, the newspaper said.

The report said the memo was written in 2018 after the then Foreign Secretary Boris Johnson visited the United States in a vain attempt to get Trump to honour the deal. Kim said in the memo that there were differences among the US president’s closest advisors, and the White House had no idea what to do after America pulled out of the deal.

Under the nuclear deal, Iran agreed to limit its nuclear activities and allow international inspectors in return for the lifting of sanctions against the country.

“I’m grateful to you for coming out on short notice and undertaking such a packed programme,” Darroch told Johnson in the memo. “The outcome illustrated the paradox of this White House: you got exceptional access, seeing everyone short of the president; but on the substance, the administration is set upon an act of diplomatic vandalism, seemingly for ideological and personality reasons – it was Obama’s deal.”

“Moreover, they can’t articulate any ‘day-after’ strategy, and contacts with State Department this morning suggest no sort of plan for reaching out to partners and allies, whether in Europe or the region,” he added.

The leak of the memo led to threats by Scotland Yard to prosecute The Daily Mail this weekend. Assistant Commissioner Neil Basu said publishing the contents of the documents could be “a criminal matter”. This, in turn, led Johnson and Jeremy Hunt, another British politician, to back the freedom of the press. Johnson said prosecution “would amount to an infringement on press freedom and have a chilling effect on public debate”.

However, Darroch resigned as the British envoy to the US after Johnson refused to say whether he would keep the ambassador in the post if he became prime minister.