On budget day, PMQs showed a Prime Minister on the back foot—and beholden to her back benches

Jeremy Corbyn decided, finally, to attack the government on Brexit today. He’s not been so keen to go that way at PMQs in recent appearances—but he took a running leap at it today.

He started with the Irish border and the lack of progress there —a comment which will surely have landed hard following Taoiseach Leo Varadkar’s comments—before spreading out his attack to go in for the government’s overall competence. In 17 months since Article 50 was triggered, he pointed out, nothing has happened. There is, he said “no strategy.”

Following the minor furore over a proposed amendment regarding the customs union earlier this week, Corbyn’s line of attack will remind pundits that the Labour leadership is unlikely to take a firm line on Brexit as long as they remain united by the belief that a Tory Brexit is unacceptable. Far from desperately triangulating, Corbyn has his options open.

From this position of relative strength, the opposition leader then waded in with the deeply embarrassing comments made by John Redwood—who doubles as a financial analyst for the investment house Charles Stanley—in which Redwood advised investors to take money out of the U.K. because of the coming Brexit slowdown. It was a nasty moment. Redwood looked rather unhappy; his features set in a mask of rictus hauteur.

And so it went: Brexit, Brexit and more Brexit. The shouting was pretty raucous. But the most significant sight was not at the despatch box, but on the government’s own back benches. It was the rows of stony-faced Conservative MPs, glum, some looking at their iPhones, packed together like a load of discarded M&S dummies. It was these disgruntled government MPs who were the weightiest presence in the Commons ahead of today’s budget.

This should worry the already-precarious Prime Minister. The clock is ticking on Brexit, and on May; but it is these benches of silent-looking men and women who will decide what happens now. They will be the ones to tear down the PM and all her hopes, along with those of this haphazard government. Can the PM dispel the air of failure? The Chancellor’s performance today will be crucial in that.