Keir Starmer is facing shadow cabinet anger for welcoming into his party a rightwing Conservative MP who has repeatedly attacked Labour over migration. Natalie Elphicke became on Wednesday the second Tory MP in two weeks to cross the floor of the Commons, dealing another major blow to Rishi Sunak. Starmer welcomed Elphicke to the Labour party at prime minister’s questions and said the Conservatives were “failing to keep our borders safe and secure”. Elphicke quit the Conservatives with a broadside against Sunak, saying that under his leadership the Tories had become “a byword for incompetence and division” and had abandoned the centre ground. But Starmer’s decision to admit her to Labour has been met with bafflement and consternation from his MPs, including some in the shadow cabinet and on the frontbench. MPs and shadow cabinet sources expressed reservations about her past comments and conduct. Labour sources said Starmer had met a hostile response over the defection at a gathering of the party’s parliamentary committee. They said he was challenged about Elphicke’s values and whether a rightwinger with her record should be welcome in the Labour party. One shadow cabinet minister said: “People are upset and angry right across the party about the decision.” Another shadow minister said: “Logically or politically, we didn’t need this … I worry that they’ll not have done sufficient due diligence on her.” They added: “Her hard-right views are a big red line too. Are we welcoming Nigel Farage next week?” Welcoming Elphicke to the Labour party at PMQs, the Labour leader asked Sunak: “What is the point of this failed government staggering on … [when] the Tory MP for Dover, on the frontline of the small boats crisis, says the prime minister cannot be trusted with our borders?” Conservative MPs were flabbergasted by Elphicke’s defection. She had been a member of the rightwing European Research Group of Tory MPs and a vocal proponent for tougher rightwing politics. One minister said her move marked the “new ERG wing of the Labour party”. Critics pointed to Elphicke’s comments on migration and strident criticism of Labour’s policies. A year ago she wrote an article for the Daily Express calling Starmer “Sir Softie” and accusing Labour of wanting “open borders”. She wrote: “Not only have Labour got no plan of their own to tackle illegal immigration, they simply do not want to.” In 2021 she clashed with the England footballer Marcus Rashford, who she said should have spent more time “perfecting his game and less time playing politics” – a reference to his campaign for free school meals – after he missed a penalty at the Euro 2020 final. She later apologised. One Labour MP said there was significant anger among some women in the party about the decision to admit Elphicke. “Most of us on the backbenches struggle to get any contact at all from the Labour leader or his team – perhaps if we were to stand in front of a few more flags or join the [European Research Group]?” An MP on the left of the party added: “I think many in the party think it’s disgusting, that we don’t need people like that in the Labour party, and that she is absolutely vile … Who in their right mind thought this was helpful?” A former shadow minister said: “Many of us didn’t fight Momentum only to see our leader welcome Reform in the front door.” Another source of controversy is Elphicke’s record of defending her former husband, Charlie Elphicke, whom she succeeded as MP for Dover after he was suspended from the Conservative party over sexual assault allegations. He was found guilty two years later. Shortly after his conviction, his ex-wife defended him in an interview with the Sun, saying he was “attractive, and attracted to, women” and that had made him “an easy target for dirty politics and false allegations”. In the summer of 2021, she became one of several Tory MPs who were given suspensions from the Commons and told to apologise for being found to have tried to influence a judge presiding over his trial. Starmer’s spokesperson defended the decision to admit her to the party. “It’s a sign of the progress that we’ve made that people recognise that on some of the key challenges facing the country, the Tories have failed,” he said. “Here is someone who is willing to make the significant step of switching across to Keir Starmer’s changed Labour party and that’s something we’re very happy to see.” A Labour source said Elphicke would not be fighting her seat at the next election, and had not been offered a job or a peerage, but could informally advise the party on housing policy. She is understood to have met Starmer once before crossing the floor. Elphicke is the third former Conservative MP to defect to Labour during this parliament. On 27 April, the former health minister Dan Poulter joined Labour with a swipe at the government’s record on the NHS. In January 2022, during Boris Johnson’s leadership, the MP for Bury South, Christian Wakeford, defected citing the then prime minister’s “disgraceful” conduct.