BORIS Johnson has reportedly hit out at the BBC over its coverage of parties that allegedly took place in Downing Street last year.

The Prime Minister, who was recently seen to be taking part in a Christmas quiz with staff, has condemned the broadcaster's coverage of multiple events in Downing Street last year as "shamefully frivolous, vengeful and partisan".

The Daily Mail reported that Johnson told friends that the corporation has neglected its "primary duty" of promoting the need for Covid booster vaccinations in the face of the Omicron variant.

He said they had "wasted" the public's time and attention on the developing scandal of senior Tories holding festive events with staff in late 2020 as the rest of the country faced restrictions that prevented them from seeing friends and family over Christmas.

An investigation has been launched by Cabinet Secretary Simon Case into an alleged party on December 18 as well as another reported gathering on November 27 and an event at the Department for Education on December 10.

READ MORE: Michael Gove's words on Boris Johnson come back to haunt him

Case will examine the purpose of the events, who attended and whether rules were followed. The report is expected in the coming week.

The story of parties led BBC bulletins and covered front pages of national newspapers after a video of former press secretary Allegra Stratton revealed she and other Downing Street aides joking about a party.

The video followed a string of denials of any parties taking place by Downing Street and the PM himself and led business at Prime Minister's Questions on Wednesday.

That same day, Johnson announced a host of new measures in a bid to stop the spread of the Omicron variant that include vaccine passports for large events and ramping up the UK's booster vaccine effort.

Johnson is facing a Tory rebellion of more than 60 MPs who are opposed to the Government's Plan B measures. The rebels are reportedly considering calling for a leadership contest as Johnson faces the prospect of a vote of no confidence in his premiership.