British police under fire for media leaks warning

British police drew criticism on Saturday for a warning to journalists during a probe into a leak that led to the resignation of the ambassador to Washington.

Neil Basu, assistant commissioner of London's Metropolitan Police, had advised media outlets "not to publish leaked government documents", saying to do so "may be a criminal matter".

The warning came as police announced they were investigating the leak of diplomatic reports from Britain's ambassador to Washington Kim Darroch, which prompted outrage from President Donald Trump and forced the envoy to quit.

Boris Johnson, the favourite to take over as Britain's new prime minister this month, said prosecuting media outlets would have "a chilling effect on public debate".

Johnson, himself a journalist and former editor, said the Darroch leaks were "embarrassing but it is not a threat to national security".

"It is the duty of media organisations to bring new and interesting facts into the public domain," he said while campaigning for the leadership of the ruling Conservatives.

Fellow Conservative MP Bob Seely, who sits on parliament's foreign affairs committee, also said the police should "think again about that".

Tim Shipman, a senior journalist at the Sunday Times newspaper known for his political scoops, said the police statement was "sinister, absurd, anti-democratic".

"Do you have any comprehension of a free society? This isn't Russia," he asked the Metropolitan Police on Twitter.

However, former defence minister Michael Fallon said journalists receiving stolen material "should give it back to their rightful owner".

"They should also be aware of the huge damage that has already been done and the potentially even greater damage to be done by further breaches of the Official