It is often said that the safest place for a British minister under pressure is at the despatch box, with the tribal roar from the government benches behind offering protection from opposition attacks. But there is nothing more revealing about the mood of the House of Commons than its silence, especially when the leader of the opposition is speaking.
Boris Johnson’s apology for breaking lockdown rules, delivered “in all humility”, appeared to land well enough with his own backbenchers, even if he was jeered by the other side. And when Keir Starmer started speaking, he was met with catcalls from the government benches which rose to roars of outrage when he described the prime minister in unparliamentary language as dishonest.
But as Starmer made the case against Johnson and highlighted the Conservatives' own role in facilitating him, they went silent, many folding their arms, others looking downwards.
“There are many decent, honourable members on the benches opposite,” he said. “They know the damage the prime minister is doing. They know things can’t go on as they are.
“And they know it is their responsibility to bring an end to this shameful chapter. Today I urge them once again. Don’t follow in the slipstream of an out-of-touch, out-of-control prime minister. Put their conscience first, put their country first.”
Johnson tried to revive the crowd behind him with a dig at Starmer's role in keeping Jeremy Corbyn in place as Labour leader but he failed to raise a murmur, and the Tory backbenches remained silent even when the Scottish National Party's Ian Blackford was speaking.
A few minutes later the most effective blow to Johnson came when former Conservative chief whip Mark Harper called on him to go, instead of asking "the decent men and women on these benches to defend what I think is indefensible".
Labour’s motion to refer the prime minister to the Commons standards committee will fail on Thursday as almost every Conservative will follow the whip and vote against it. And Johnson is probably safe from a challenge to his leadership for now, not least because his party does not want to parade its divisions ahead of next month’s local elections.
But the prime minister could face fines for further lockdown-breaking parties, straining the forbearance of his backbenchers as they watch the polls showing Labour ahead on every issue and predicting that one Conservative MP in three is on course to lose their seat.