Boris Johnson scuttled out of the House of Commons chamber after being given a roasting from one of his own senior MPs.
Sir Graham Brady, chair of the influential 1922 Committee of Tory backbenchers tore his Covid plan to pieces, calmly and sternly informing the PM that he could not vote for his plan.
The Government faces a furious rebellion from Tory MPs who believe their constituencies have been unfairly placed under strict tiers - and that the Government has not published enough evidence to justify the measures.
And after Sir Graham's attack from the Tory benches, the PM appeared to be in no mood to hear more of his MPs complaining - and quickly left the chamber after the senior Conservative's speech.
Sir Graham said he had been left with "no choice" but to oppose the Covid-19 regulations.
He said his Altrincham and Sale West constituency had been "unfairly" placed in Tier 3, as he criticised the impact assessment published by the Government.
Sir Graham told the Commons: "I looked in vain at the document published late yesterday for any explanation or any route being set out as to how we would reach that lower tier.
"There was no serious attempt in that document to provide an answer.
"In the absence of that serious and compelling case, I have no choice but to oppose these measures."
Sir Graham said he believed Mr Johnson's instincts are "not so different from mine" and recognised the difficult decision the Prime Minister faced, before stressing the need for freedom to be regarded as "precious".
He told the Commons: "If Government is to take away fundamental liberties of the people whom we represent, they must demonstrate beyond question that they're acting in a way that is both proportionate and absolutely necessary.
"Today, I believe the Government has failed to make that compelling case.
"The benefit of the doubt that this House has extended to the Government in March and since is harder to take for granted in December."
