WASHINGTON - Donald Trump abandoned the Iran nuclear deal to spite Barack Obama, according to a leaked memo written by the UK's former ambassador in the US.

Sir Kim Darroch described the move as an act of "diplomatic vandalism", according to the Mail on Sunday.

The paper says the memo was written after the then Foreign Secretary Boris Johnson appealed to the US in 2018 to stick with the nuclear deal.

The latest leak came despite the Met Police warning against publication.

The first memos criticising President Trump's administration, which emerged a week ago, prompted a furious reaction from the US president and resulted in Sir Kim resigning from his role.

The Mail on Sunday reports that Sir Kim wrote to Mr Johnson informing him Republican President Trump appeared to be abandoning the nuclear deal for "personality reasons" - because the pact had been agreed by his Democrat predecessor, Barack Obama.

Under the deal, Iran agreed to limit its sensitive nuclear activities in return for the lifting of crippling economic sanctions. 

However, President Trump said he did not think that the deal went far enough in curtailing Iran's nuclear ambitions and reinstated US sanctions after withdrawing from the deal in May 2018.

The British ambassador's memo is said to have highlighted splits amongst US presidential advisors; he wrote that the White House did not have a strategy of how to proceed following withdrawal from the deal.(FA)