Investigation follows the resignation of UK Ambassador Sir Kim Darroch.
On Friday, the London Metropolitan Police made the announcement that:
'There has been damage caused to UK international relations, and there would be a clear public interest in bringing the person or people responsible to justice.'
The Counter Terrorism Command, the unit responsible for investigating alleged breaches of the UK's Official Secrets Act, will lead the probe. (This is the same Counter Terrorism Command that lost the forensic details of 144 terror suspects in 2018.)
Cables from Sir Kim Darroch, the UK's ambassador to the United States, were leaked to the Mail on Sunday last week, in which Darroch described US President Donald Trump as 'inept' and 'incompetent' and his administration as 'dysfunctional' and at risk of collapsing in 'disgrace'.
Trump responded by attacking Darroch in a series of tweets, saying that the ambassador 'is not well liked or well thought of within the US' and that his administration 'will no longer deal with him'.
Darroch resigned on Wednesday, though many commentators and even government officials standing up for him pointed out that he was perfectly entitled to provide a frank assessment of his host country's government.
Under diplomatic conventions and British law, the contents of diplomatic mail are meant to be confidential and were only supposed to have been seen by a handful of UK civil service officials.
The incident has caused the British government considerable embarrassment, especially considering that the partnership between the two countries was just trumpeted during Trump's state visit to the UK in early June.
It has also figured prominently in the Conservative Party leadership contest, with candidates vying to replace Theresa May as the prime minister taking opposing sides on the Darroch issue.
Darroch resigned after the frontrunner, Boris Johnson, refused to publicly stand up for him during a televised debate with his rival for the post, current Foreign Secretary Jeremy Hunt.
The ambassador indicated his decision to resign was influenced by Johnson's refusal, since he is overwhelmingly likely to be the next prime minister.
The Metropolitan Police called on members of the public with information about the leaks to come forward and implored the perpetrator to 'turn yourself in at the earliest opportunity, explain yourself and face the consequences'.