Keir Starmer put on the back foot over treatment of Diane Abbott

Keir Starmer began his day by taunting Rishi Sunak for the faltering start to the Conservative’s election campaign.

On a visit to Wales the Labour leader said Sunak thought he was laying a trap by calling a snap summer election but a series of blunders since meant he had “caught himself in his own ambush”.

By the evening, however, it was Starmer who was on the back foot, with the Tories crowing that he was being undermined by his own deputy, Angela Rayner, over the fate of Diane Abbott.

In an interview with the Guardian, Rayner said she saw no reason why Abbott should not be allowed to stand again for Labour now the whip had been restored, although she indicated Abbott might yet opt to retire.

That had been the original plan, according to Labour insiders, until it was jeopardised by an unauthorised briefing that she would be barred from standing again, riling her allies and leaving some senior party figures shaking their heads in despair.

“It was totally counterproductive,” one admitted. “What were they trying to achieve? We were hoping that it could all be handled with dignity but they couldn’t resist giving her a kicking on the way out.”

Starmer has been accused of blocking leftwing MPs and jetting allies into safe seats. Rayner admitted it was “unfortunate” that some selections were taking place this late but the timing was inevitable to fill vacant seats. She denied the moves were a “purge” of the left.

There were suggestions – not denied by the party – that Sue Gray, Starmer’s chief of staff, has been concerned about the handling of Abbott’s case and that, rather than ending up in a situation that suited everybody, they were now dealing with the fallout from one that suited no one.

The way Abbott’s future has been handled and the spate of Starmer allies being installed in safe seats has made some in the party uncomfortable. There is also concern it could alienate ethnic minority supporters and voters.

One insider said the decision was being made by six white men and “that’s why you end up with this kind of pickle”. But they added that there was little appetite by Labour HQ staff or shadow ministers to make a fuss during the election campaign. “I don’t think there’s the capacity or the willingness to rock the boat internally.”

Another senior Labour figure said: “I can’t deny that I’m dismayed by this by the way this is being run. The way Diane has been treated is outrageous. These people could be ministers running government departments shaping the lives of hundreds of millions of people.”

Others felt the row was a distraction from the issues that voters wanted to focus on, and risked undermining Starmer’s criticism of the Tories that a vote for them would mean more chaos and infighting.

“That’s not to say that resolving the Diane situation isn’t important but we are trying to build to the future,” one said, before adding that Abbott could have decided to cooperate sooner.

One Labour figure suggested that as a result of Rayner’s intervention, which was understood not to have been authorised by Starmer’s office, it was more likely the party would let Abbott decide her own future.

“With Rayner coming in, my gut feeling is that it’s 60/40 that they will let run [Abbott] again. It’s just not worth it. You can’t win every battle. Let’s focus on getting all the good people elected,” they said. “Though there are MPs arguing that we should buckle down for a couple more days and we’ll get through it, and by week-four of the campaign people will have forgotten about it.”

Other Labour officials suggested this was the plan all along. “We’d much rather get this news out the way now so it doesn’t distract next week,” one said. “Let this week be the controversial impositions – it’s happened under every leader.”

There are even whispers that a war with the left is one that those leading Labour’s campaign, Morgan McSweeney and Pat McFadden, wish to wage, in the hope that it once again underlines how the party has moved on from the Jeremy Corbyn era.

Related: Which leftwingers won’t be Labour candidates in the general election?

If Labour does decide to go ahead with blocking Abbott there will be a showdown moment at a meeting of the party’s national executive committee on Tuesday, when it rubber stamps the party’s candidates.

Alternatively, a three-person NEC panel could call her in for an interview before Tuesday to decide whether or not she should stand. If they opted to block her, there would be a last-minute process to find a replacement candidate.

One senior Labour source said that the leader’s office may have already started taking the temperature of the NEC as there could be a backlash among members even though it is majority Starmer-supporting.

The Labour NEC member Gemma Bolton, a left-winger, told the BBC she would vote to endorse Abbott and that she hoped by the time of the meeting there would be a “clear consensus Diane should be a candidate”.

But other Labour leftwing candidates are, notably, keeping their heads down. “If Keir can do this to Diane, he can do it to anyone,” one said. “But hopefully they’ll see their plans are going down terribly and will decide to stop the factionalism and focus on what the public really wants.”