A Tory MP and former health minister has staged a dramatic defection to Labour, saying the Conservatives have become a “nationalist party of the right” that has abandoned ­compassion and no longer prioritises the NHS. Dr Dan Poulter, the MP for Central Suffolk and North Ipswich, who works part-time as a mental health doctor in an NHS hospital, announced he was resigning as a Tory MP and would be taking the Labour whip until the next election in an exclusive interview with the Observer. He said he would not seek re-election to the House of Commons at the next general election. But, writing in the Observer, he says he envisages a role advising the Labour party on its policies on mental health while focusing more on his NHS work. Poulter said his experiences on more than 20 night shifts over the last year in a severely overstretched accident and emergency department had been “truly life-changing” and persuaded him to defect to the only party he believed was now really committed to investing in improving the NHS. He said: “I could not go on as part of that. I have to be able to look my NHS colleagues in the eye, my patients in the eye and my constituents in the eye. And I know that the Conservative government has been failing on the thing I care about most, which is the NHS and its patients.” The Observer understands that discussions between Poulter and senior Labour figures have been going on for many months at the highest levels about the timing and organisation of his likely defection, as well as advisory roles he could play in future in developing the party’s health policies, with the benefit of his firsthand inside knowledge. The defection has, however, been kept the tightest of secrets, with only half a dozen people in the party knowing it was coming before the Observer broke the news. A one nation Tory on the left of the party, Poulter has regularly made his disquiet clear about the direction of government policy since David Cameron’s premiership, and it is understood that he has been frustrated by subsequent Tory prime ministers’ lack of interest in his views on NHS reform. The shock defection – the first by a Tory MP to Labour since Christian Wakeford crossed the floor in 2022 – is another severe blow to Rishi Sunak before Thursday’s council and mayoral elections, in which the Tory party is expected to lose up to a half of its remaining local authority seats. Heavy losses and failure to hold on to key mayoralties such as the West Midlands and Tees Valley are likely to reopen speculation about a possible pre-election leadership challenge to the prime minister. In the run-up to the next general election, the future of the NHS will be a vital battleground, and Labour is known to be keen to use Poulter’s inside knowledge to maximum effect. Poulter was first elected to parliament in 2010 and served as a health minister under Cameron from 2012 to 2015. Since then, he says, he has seen a progressive “rightward drift” in the party’s policy and thinking that has left him feeling increasingly uncomfortable. He described Liz Truss’s brief and disastrous premiership as a “shattering moment” for moderates in the party like him, and for middle-ground voters. “It is very difficult to forget that,” he said, adding that his constituents had become poorer directly as a result of Truss’s mistakes on the economy. “The Conservative party’s values have changed over the past eight years,” he said. “The values of the Conservative party under David Cameron were different values and the priorities were very different. David Cameron undoubtedly had a very strong commitment to the NHS. “Since he ceased to be prime minister eight years ago, the health service has ceased to be an area of priority for the Conservative party, and that is now showing in the strain on the frontline and the deterioration of care for patients.” He added: “It feels to me that the Tory party has gone from being a pragmatic, centrist, centre-right party which focused on and understood the importance of public service and the state to deliver certain things …and had a compassionate outlook on key issues. It has gone from that and feels like it has become a nationalist party of the right, much more of what we see in Europe. “It is not to say all [Tory] MPs are like that. There are good MPs, but it feels that the party is ever moving rightwards, ever presenting a more nationalist position rather than a position that actually focuses on what a lot of people want to see, which is a level of compassion from government but also well-run public services.” Poulter said he wished Sunak well in what was a very difficult job and that the prime minister had always been very civil towards him. But he lavished praise on Keir Starmer for reforming the Labour party since 2019 and for his clear commitment to the ideals of public service. In the case of the NHS, he said, the party’s focus on preventative care, child health and the social causes of poor health were key. “One of the things I really like about Labour party policy on the NHS is the focus on the social determinants of poor health and actually recognising that tackling poverty, poor housing, all those issues, particularly giving children from poorer backgrounds better chances and focusing on child health,” he said. “That is something Labour understands that the Conservatives really don’t – and that, for me, is something that makes the Labour party the party that can be trusted with delivering the reforms that are needed to get the NHS back on its feet.”