Police in Britain have opened an investigation into a leak of confidential memos that led to the resignation of the British ambassador to Washington.
Kim Darroch quit on Wednesday after Donald Trump called him "stupid" and "wacky" following the publication of the confidential memos by a newspaper. In them, Mr Darroch called Mr Trump's administration inept.
London's Metropolitan Police said its counter-terrorism command, which takes national responsibility for investigating allegations of criminal breaches of the Official Secrets Act, was leading the investigation.
"Given the widely reported consequences of that leak I am satisfied that there has been damage caused to UK international relations, and there would be clear public interest in bringing the person or people responsible to justice," Met Assistant Commissioner Neil Basu said in a statement.
The leaked memos have cast a shadow over ties between Britain and the United States and taken centre stage in the contest to be the next British prime minister.
Boris Johnson, frontrunner in that race, has been heavily criticised by MPs in his own party and the opposition for failing to defend the ambassador.
In his statement, Mr Basu urged the person or people who leaked the memos to turn themselves in.
"I would say to the person or people who did this, the impact of what you have done is obvious," he said. "However, you are now also responsible for diverting busy detectives from undertaking their core mission. You can stop this now. Turn yourself in at the earliest opportunity, explain yourself and face the consequences."
Mr Basu said journalists and publishers could be in breach of the law if they published further details from the memos.
"I would advise all owners, editors and publishers of social and mainstream media not to publish leaked government documents that may already be in their possession, or which may be offered to them, and to turn them over to the police or give them back to their rightful owner, Her Majesty's Government."
The memos said rumours of "infighting and chaos" in the White House were mostly true.
The head of Britain's diplomatic service, Simon McDonald, said this week he was "bracing" himself for further leaks, which he described as "the worst breach of trust in our service in my career".
"I fear there may be more," he said. "People are shaken by what has happened. The basis on which we have worked all our careers suddenly feels as if it is challenged."
After Mr Darroch's resignation, a diplomatic source told Reuters that a lack of support from Mr Johnson during a televised debate with his rival for the premiership, foreign minister Jeremy Hunt, had been a factor in the envoy's decision to quit.
In an interview with the BBC, Mr Johnson denied he was responsible for Mr Darroch's resignation, but admitted his comments had been a factor.