Rishi Sunak is winning his arm-wrestling contest with Boris Johnson

It was a good week for the prime minister and a bad one for his predecessor-but-one.

A Johnson-led revolt by Eurosceptics against Sunak’s deal with the EU fizzled out and Johnson’s very uncomfortable hearing before the Commons Privileges Committee leaves him in deep trouble over claims he lied to parliament over Partygate.

Sunak’s strong performance in recent weeks and Johnson’s woes have killed the prospect of Johnson mounting a coup and remarkable comeback before the general election. Crucially, Sunak now has a cushion against expected Conservative losses in the May local elections in England, which Johnson’s fan club hoped would provide his springboard.

Where do Sunak’s improving prospects leave Labour? Keir Starmer’s strategy when Sunak became PM was to repeatedly attack him as a “weak” leader pushed around by his own party. Tactical retreats to avoid backbench Tory rebellions fuelled that impression. But it is now dawning on some senior Labour figures that this line might be past its sell-by date because Sunak is looking stronger.

Starmer was wise to pledge in advance that Labour would support Sunak’s agreement with the EU on the Northern Ireland protocol. In the event, only 21 Tories joined Johnson in voting against it and Sunak won the Commons with a thumping majority of 486 and didn’t need Labour’s backing.

If he had done, as Labour hoped, Starmer could have again branded him “weak” and not in control of his party. Instead, the vote made Sunak look strong for standing up to the hardline Brexiteers and strengthened his grip on the Tories.

Knowing that an incoming Labour government could not splash the cash, Starmer’s pitch has rested heavily on his party offering competence. It worked when the voters could see that Johnson and then Liz Truss were patently incompetent.

But after Sunak’s improved performance of late, I detect the first signs of jitters among some Labour figures. As one told me: “Is competence now going to be enough to win an election against Sunak?”

Labour isn’t in panic mode yet. The country’s underlying economic problems, with living standards set to fall by 5.7 per cent over the current and next financial years, will make it hard for the Tories to generate a “feelgood factor” before next year’s election. “Time for change” after 14 years of Tory rule will be a powerful Labour message.

Sunak’s advisers warn Tory MPs the damage to the party brand will not be repaired overnight, and the opinion polls will take months to turn round. But there’s a flicker of hope for the Tories: Sunak’s ratings are higher than his party’s and might just be starting to raise them.

In eight of the 12 most recent polls, Labour’s advantage is below the 20-point average lead it has enjoyed. Not a trend yet, but it might become one.

If Sunak can show voters he is making progress on his key pledges and clearing up the mess he inherited, a Labour campaign based on competence would look even more inadequate. Labour strategists doubt Sunak can transform himself into a strong candidate in the presidential contest the Tories plan – in which he would ask for an extension of his short first term rather than an unprecedented fifth Tory one. But if the election becomes a choice between two technocrats, some voters might be tempted to stick with the one with a track record in government rather than take a chance on Starmer.

Labour will have to offer a real choice, and something different. Yet it often seems the two main parties are converging in the centre ground. The stealing of Labour’s best clothes with a big childcare package in the Budget discomforted Starmer’s party.

Starmer is damned if he does, or doesn’t, set out policies. He is now responding to demands from critics who want more “flesh on the bones” of his five “missions” for a Labour government.

But when on Thursday he set specific targets to reduce crime, including halving the level of violence against women and girls, he was accused by some of risking failure since it would be hard to hit such ambitious goals.

Sunak will respond on Monday with a raft of measures to tackle anti-social behaviour. Again, the two parties contesting the same ground. (Although the Tories would never admit it, Starmer, the former director of public prosecutions, does get under their skin on crime.)

Sunak’s purple patch should give Labour pause for thought. As one Labour MP put it: “Our poll lead is based on an anti-Tory vote, but we can no longer assume that will remain as big as it is. We need to win positive support for our agenda.”