Boris Johnson’s Jimmy Savile smear of Keir Starmer has been blamed for a mob ambushing the Labour leader near the houses of parliament – prompting a wave of Tory MPs to criticise their leader.

Police had to bundle the opposition leader into a car as the group, some protesting about Covid restrictions and shouting “traitor”, followed him and shadow foreign secretary David Lammy from outside Scotland Yard.

There were angry clashes with police after Starmer was escorted into a police car on the Victoria Embankment shortly after 5pm on Monday. Starmer faced baseless allegations of “protecting paedophiles” and chants about the sex offender from protesters before being bundled into a police car for protection.

After some Conservative MPs said Johnson last week accusing Starmer of having “used his time prosecuting journalists and failing to prosecute Jimmy Savile” while director of public prosecutions for stoking the abuse, the PM condemned the “completely unacceptable” incident. Notably he did not apologise.

Footage posted to social media showed Piers Corbyn, the Covid-19 conspiracy theorist brother of former Labour leader Jeremy, addressing the crowd before the incident and later leading chants of “resist, defy, do not comply”.

Video showed Starmer, surrounded by police, being followed down the street while being targeted with shouts of “why aren’t you opposing?” and “traitor”.

“Why did you go after Julian Assange, why did you go after journalists?,” one man shouted.

It was understood Starmer was not harmed during the incident and was soon back at his desk.

After he was taken to safety, an officer was called a “pathetic little thug” during angry exchanges.

Protesters were seen displaying signs opposing mandatory vaccination and the use of restrictions to prevent Covid-19 deaths.

After footage of the confrontation spread on social media, MPs from across the political spectrum hit out at the prime minister’s slur against Starmer.

After the attack, Tory MP Julian Smith linked the incident to Johnson’s Savile smear in the Commons last week.

He tweeted: “What happened to Keir Starmer tonight outside parliament is appalling. It is really important for our democracy & for his security that the false Savile slurs made against him are withdrawn in full.”

Another Conservative MP, Robert Largan, added: “I agree with Julian. Words matter. What we say and how we say it echoes out far beyond parliament. It can have serious real world consequences. Elected representatives have a responsibility to lower the temperature of debate, not add fuel to the fire.”

Deputy speaker of the house of commons, Eleanor Laing, said the attack was “unacceptable. Period.”

She tweeted: “Elected representatives must be able to go about their work without the fear of verbal or physical attacks.”

“It doesn’t matter which political party you support we all must stand up for freedom of speech and the rule of law.”

Another Tory MP, Aaron Bell, said: “Physical intimidation has no part in our democracy, and we all have a responsibility to debate in a measured and accurate way.”

After he was heckled alongside Starmer, Lammy tweeted alongside a video clip of the incident: “No surprise the conspiracy theorist thugs who harassed Keir Starmer and I repeated slurs we heard from Boris Johnson last week at the despatch box.

“Intimidation, harassment and lies have no place in our democracy.

“And they won’t ever stop me doing my job.”

He added: “My thanks to the Met Police who helped get me safely back to parliament.”

Labour MP Chris Bryant tweeted: “This is appalling. People were shouting all sorts at Keir, including ‘Jimmy Savile’. This is what happens when a prime minister descends into the gutter and recycles lies from hard-right conspiracy theorists. Political poison has an effect. Johnson has no moral compass.”

A Labour source told HuffPost UK: “Boris Johnson and his cabinet chose to lie down with the dogs – and now the whole lot of them are covered in fleas.”

Johnson later tweeted: “The behaviour directed at the leader of the opposition tonight is absolutely disgraceful. All forms of harassment of our elected representatives are completely unacceptable.

“I thank the police for responding swiftly.”

Scotland Yard said two arrests were made after the clashes.

A Metropolitan Police statement said: “Shortly after 5.10pm on Monday, February 7, a man who had been surrounded by a group of protesters near to New Scotland Yard, was taken away from the scene by a police car.

“A man and a woman were arrested at the scene for assault of an emergency worker after a traffic cone was thrown at a police officer.

“They have been taken into custody.”