Boris Johnson was branded a “pathetic spectacle” by Sir Keir Starmer, before Labour MPs waved and shouted “bye bye” to the Prime Minister.

Labour leader Sir Keir said ministers resigning from Mr Johnson’s Government have not got a “shred of integrity” given the level of recent scandals, adding it was the “first recorded case of the sinking ships fleeing the rats”.

He opened Prime Minister’s Questions by reading out the testimony of a man who accused former Government deputy chief whip Chris Pincher (Tamworth) of assault.

Mr Johnson insisted he was not going to “trivialise what happened” when then asked if he ever said “Pincher by name, Pincher by nature”, with Sir Keir noting: “No denial.”

After Mr Johnson sought to criticise Sir Keir’s “muddled” response to Brexit and other matters, he added: “He is himself facing a criminal investigation, for which he asked me to resign.”

Sir Keir countered: “What a pathetic spectacle. The dying act of his political career is to parrot that nonsense.

“As for those who are left, only in office because no-one else is prepared to debase themselves any longer: the charge of the lightweight brigade. Have some self-respect.

“For a week he’s had them defending his decision to promote a sexual predator … anyone with anything about them would be long gone from his frontbench.

“In the middle of a crisis, doesn’t the country deserve better than a Z-list cast of nodding dogs?”

Labour former minister Chris Bryant could be heard saying: “They’re not even nodding now.”

Mr Johnson replied: “It’s exactly when times are tough, that when the country faces pressures on the economy and pressures on their budgets and when we have the biggest war in Europe for 80 years, that is exactly the moment that you’d expect a government to continue with its work, not to walk away, and to get on with the job.”

Sir Keir said: “The only thing he’s delivering is chaos.

“I started this session with a quote from the young victim in all this. How he froze when he was attacked.

“When I was prosecuting rapists, I heard that from victims all the time.

“Victims said they froze because it’s not about sex, it’s about power, and the power the disgraced Government minister had was handed to him by that Prime Minister – and he’s only in power because he’s been propped up for months by a corrupted party defending the indefensible.

“So it’s no longer the case about swapping the person at the top, isn’t it clear the only way the country can get the fresh start it deserves is by getting rid of the lot of them?”

Mr Johnson was heckled with shouts of “bye bye” from opposition MPs as he replied: “The difference between this Government and that Opposition is we have a plan and they do not, and we’re getting on with it.

“They want to focus on this type of issue, we’re going to get on with our jobs.”