Morgan tweeted: "Boris Johnson told a disgusting lie in Parliament yesterday about Sir Keir Starmer 'failing to prosecute Jimmy Savile.' He did it to deflect attention from his previous lies about Partygate. If a minister lies to the House, he has to resign."
Watch: PM uses Jimmy Saville quip to criticise Starmer in Commons
Boris Johnson told a disgusting lie in Parliament yesterday about Sir @Keir_Starmer 'failing to prosecute Jimmy Savile.'
He did it to deflect attention from his previous lies about #Partygate .
If a minister lies to the House, he has to resign.
— Piers Morgan (@piersmorgan) February 1, 2022
Referring to the time when Keir Starmer was director of public prosecutions Johnson said: "Who used his time prosecuting journalists and failing to prosecute Jimmy Savile, as far as I can see – he chose to use this moment to continually pre-judge a police inquiry."
Sir Keir has since called Johnson's comment a "ridiculous slur".
The Metropolitan Police have now launched their own investigation into whether the government broke the law by holding social gatherings during the coronavirus lockdown.
Deputy Prime Minister Dominic Raab was asked on BBC Radio 4's Today programme if he would repeat the "extraordinary and baseless allegation" without parliamentary privilege.
Raab said: "This is the cut and thrust of parliamentary debates and exchanges... I'm certainly not repeating it. I don't have the facts to make comments like that."
Parliamentary privilege allows members of the House of Commons and the House of Lords to have freedom of speech and immunity from defamation when speaking in Parliament.
Morgan also tweeted: "Boris Johnson and his No10 staff repeatedly ignored the rules they ordered the rest of us to obey ‘to save lives’, so they could party during the biggest health crisis for 100 years. That’s the story, and whatever his defenders say, it’s utterly outrageous."
It is not the first time Morgan has called for the Prime Minister's resignation.
The 56-year-old former Good Morning Britain presenter tweeted a link to a post about a leaked email showing Downing Street staff were invited by the prime minister's private secretary for drinks on 20 May 2020 when the country was in lockdown and an official announcement the same day had told the public they must stick to meeting in pairs only outdoors.
Morgan shared a photo of himself and his son socially distancing on the same day, writing: "On the day (May 20, 2020) that Boris Johnson attended his No10 party where 100 people were invited to ‘bring a bottle’, I met my eldest son for first time in 2 months, & we stayed this far apart, without anyone else there, because that was BORIS JOHNSON’S BLOODY RULE."
He added: "We all have similar stories, some obviously deeply distressing involving sick and dying loved ones. Britain’s prime minister separated families for months on end, often in their darkest hours, but secretly ignored all those rules himself to party. Just outrageous hypocrisy."
Watch: Keir Starmer said Boris Johnson's Savile claim was a 'ridiculous slur'