It is often suggested by political observers, more in hope than in expectation, that if a challenge to Keir Starmer’s leadership were to emerge this side of a general election, it would come from his deputy, Angela Rayner.

She has some cause, after all, to feel that she is not valued by her boss: he has tried in the past to demote her and has conducted at least two reshuffles without informing her in advance. Even Tom Watson was kept more abreast of what Jeremy Corbyn was doing (most of the time) and theirs was one of the most dysfunctional political relationships since the one before it.

Unfortunately for any ambitions Rayner might have harboured, yesterday’s outing at Prime Minister’s Questions, where she was deputising for Starmer in the absence of the prime minister abroad, will not have increased the chances of securing enough nominations to mount a challenge, even if that was her intention. She has received a decent press in recent years for her plain-speaking, working class approach, delivered in her trademark, no nonsense, northern fashion. The London-based media especially loves this sort of thing and imagines that highlighting this approach somehow burnishes its progressive credentials, when in fact it merely exposes its failure to give due attention to the many capable women MPs with northern accents who have been doing a fine, though less high profile, job for years.

Yesterday was not Rayner’s finest moment, and it wasn’t entirely her fault. Despite expectations, she entirely misjudged the mood, seeking to win advantage on the subjects of Partygate (again), Saudi Arabia, renewables, the peerage for Evgeny Lebedev, and even the case of Nazanin Zaghari-Ratcliffe, released from Iranian captivity yesterday, an event that so overjoyed the nation that any sensible politician would have been most wary of seeking to win party political points over it. But that’s what Rayner sought to do, reminding everyone of Johnson’s unfortunate comments in 2017 that may have encouraged Iran to hold onto her for longer.

It was an unnecessary jibe which just felt out of place in a Commons that felt ready to celebrate the release with the rest of the country. Voters like to hear politicians uniting behind a single cause; they even enjoy hearing opposition MPs praising government ministers when they get something right (that enjoyment perhaps being all the more appreciated because of its rarity). But to do so would have meant conceding that not everything Johnson’s government does is intrinsically evil, so Rayner ruled that out.

In 1994, when he made his debut as Leader of the Opposition at the despatch box, Tony Blair’s very first words to the then prime minister, John Major, were in praise of the government’s efforts to secure peace in Northern Ireland. No one thought that the Labour leader was letting anyone off the hook by making common cause with the government.

Rayner’s caution, her profound reluctance to accept that occasionally the Government does stuff in exactly the same way that a Labour government would do it, speaks to her, and her front bench colleagues’, innate insecurity about the electorate’s view of them. A more confident opposition would have no fear of praising their opposite numbers when they get things right, as Liz Truss has done over Zaghari-Ratcliffe, and as Johnson and his defence secretary, Ben Wallace, have over Ukraine.

Since the unexpected (and recently shrinking) polling lead that Partygate gave Labour at the end of last year, its front benchers have been desperately trying to maintain it by steadfastly refusing to allow the Government credit for anything at all. When it looked like Boris Johnson’s solidarity with Ukraine and his robust response to Russian belligerence was in danger of going down well internationally – especially among Ukrainians themselves – Labour tried to make the most of the government’s cack-handed and sluggish response to the refugee crisis provoked by the war, seeking to give the entirely erroneous impression that accommodating displaced Ukrainians 1500 miles away from their homeland was more important than supplying the Ukrainian military with state-of-the art weapons with which to defend themselves.

Labour MPs got a reminder yesterday that Rayner is far from being the great hope that some on the Left have imagined her to be. It turns out that in Starmer’s absence, there really isn’t any obvious contender who can take on the Government any more valiantly or thoughtfully than he does himself. This is good news for the Labour leader, although, to be fair, there never was any serious prospect of the necessary one fifth of Labour MPs needed to provoke a pre-election leadership contest nominating her anyway.

Instead of fretting about the nightmare scenario in which the Ukraine crisis allows Boris Johnson to recover his polling magic and lead his party to another general election victory, Labour needs to substitute oppositionalism for judgment, something that Starmer promised in his very first comments as Labour leader in April 2020. He has shown himself capable of setting such an example, but few of his front benchers have been able to follow it.

And his deputy certainly can’t. Or won’t.

Labour looks like a one-man show right now. Starmer needs to take full advantage of that.