Labour deputy leader Angela Rayner has described Boris Johnson's decision not to answer on if he attended an alleged Downing Street drinks party as "despicable" and that he's treated the British public "with contempt".

This comes in the wake of a leak of an email on Monday (January 10) from the Prime Minister's principal private secretary Martin Reynolds, when he invited 100 Downing Street staff to a "bring your own booze" garden party during the first lockdown in May 2020.

The disclosure triggered a new wave of public anger following the reports last year of parties in the run up to Christmas 2020, with Tory MPs openly warning Mr Johnson his position will be untenable if he has been shown to have lied.

Appearing on Good Morning Britain, Rayner didn't hold back in her criticism of the Prime Minister.

She said: "Now fundamentally I think the British public are now starting to see that Boris Johnson is not fit to be Prime Minister.

"He can't answer a simple question of 'Was you at this party at your residence or not when people weren;t able to see their loved ones who were dying?'

READ MORE: Full timeline of alleged No 10 gatherings and parties in 2020

"It's pretty despicable that he's treated the British public with contempt by not answering that question and trying to hide behind Sue Gray's investigation."

Sue Gray is the civil servant and Cabinet Office official who is investigating the allegations surroundig the parties.