Kim Darroch, the former British ambassador to the United States, said the Trump administration was "set upon an act of diplomatic vandalism" in its decision to abandon the Iran nuclear deal, the Daily Mail reported Saturday, citing leaked cables.

The report comes following news last week that Darroch sent diplomatic cables describing President Donald Trump as "inept," "insecure" and "incompetent," a British government official confirmed to CNN. Darroch has since resigned, saying it was "impossible" for him to continue.

According to the Daily Mail, the former ambassador said Trump seemed to be discarding the Iran nuclear deal for "personality reasons," as the deal had been agreed to by former President Barack Obama. The paper also reported that Darroch hinted at discord brewing between Trump's closest aides and said the White House had failed to produce a "day-after" plan on how to handle the aftermath of withdrawing from the deal.

The White House told CNN it has no comment on the story.

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

A leak of diplomatic cables led to the resignation of Kim Darroch, Britain’s ambassador to the United States.CreditCreditAlex Wong/Getty Images

According to BBC, Darroch’s memo to Johnson says: "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."

The British government has launched an internal Whitehall inquiry into the leak. 

The Daily Mail has defended its decisions to publish further details from the memos.

A spokesman for the newspaper said it was in the public interest and revealed "important information" on the UK's attempts to stop President Trump abandoning the Iran nuclear deal.

He added: "What could be more in the public interest than a better understanding of how this position was reached, which may have serious consequences for world peace?"

In response, a Foreign Office spokesman called it a "totally unacceptable leak" of "sensitive material" and called for the source of the leak to "face the consequences of their actions".

Trump said Monday that the White House would no longer deal with Darroch, and the UK Foreign Office announced Darroch's resignation Wednesday. The former ambassador made his decision to step down after seeing that Johnson, the current frontrunner to replace Theresa May as British prime minister, had refused to support him during Tuesday night's leadership debate, a British government official confirmed to CNN.

A UK Foreign Office spokesman told CNN on Saturday that whoever leaked the cables "should face the consequences of their actions."

Police in the UK have opened a criminal investigation into the leaked diplomatic cables that led to Darroch's departure. Metropolitan Police Assistant Commissioner Neil Basu claimed Friday that there is a "clear public interest in bringing the person or people responsible to justice."

At the time the U.S. withdrew from the deal, senior Trump administration officials -- including Secretary of State Mike Pompeo and the Director of National Intelligence Dan Coats said Iran was adhering to its commitments under the deal.

Earlier this week, Trump tweeted that Iran "has long been secretly 'enriching'," a claim that has been contradicted by the International Atomic Energy Agency, whose monitors were tasked with ensuring that Iran was complying with the terms of the 2015 deal, as well as by independent experts and by Trump's own top intelligence officials.