The UK Prime Minister encountered embarrassment during a TV debate with Labour Party leader Jeremy Corbyn, after the latter brandished a copy of a leaked confidential government document ahead of the UK Parliamentary elections in December 2019.

UK Prime Minister Boris Johnson has reportedly ordered a probe launched into the leak of confidential government documents ahead of the parliamentary election campaign in December 2019, according to the Daily Mail.

The Daily Mail cited government sources saying that Johnson is concerned that there is a ‘Labour mole’ inside the cabinet, following the leak.

The secret document, obtained by Labour leader Jeremy Corbyn, was reportedly a Treasury analysis claiming that the prime minister’s Brexit deal will include checks on goods passing between Northern Ireland and other parts of the UK.

Johnson claimed, in response to Corbyn brandishing the document during a TV debate between the two leaders, that the report is “nonsense”. A senior Whitehall official reportedly argued that the paper was an ‘initial appraisal’ prepared by junior civil servants, and it had not been signed by top cabinet officials.

“There was a pattern through the campaign of unhelpful documents being released. The intention was to embarrass the Government. It does suggest we have a Labour mole and we are going to root them out,” an unnamed government source said, cited by the Daily Mail.

Whitehall officials are also worried about another leak concerning London's preparations to depart the EU by the deadline of the Brexit transitional period. The cabinet has launched a separate probe into the release of minutes from recent UK-US trade talks.