Tory MP Dan Poulter has defected to the Labour Party in the latest hammer-blow to Rishi Sunak’s authority.
The former health minister and doctor said he no longer trusted the Conservatives with the NHS.
He also said the Tories had “become a nationalist party of the right” since David Cameron quit as leader eight years ago.
In an interview with the Observer, Poulter, who was elected MP for Central Suffolk and North Ipswich in 2010, said his experiences on more than 20 accident and emergency ward night shifts in the past year had been “truly life-changing”.
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.”
Poulter said the Conservatves’ values “have changed” since Cameron stood down as prime minister in the wake of the 2016 Brexit referendum.
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.”
Labour leader Keir Starmer said: “It’s fantastic to welcome Dr Dan Poulter MP to today’s changed Labour Party.
“It’s time to end the Conservative chaos, turn the page, and get Britain’s future back. I’m really pleased that Dan has decided to join us on this journey.”
Shadow health secretary Wes Streeting said he was “proud” to welcome Poulter to Labour.
He said: “As a frontline clinician, he’s seen the damage that 14 years of Conservative government have done to our NHS. Delighted to have his support and look forward to working with him, especially on mental health reform.”
Poulter’s defection to Labour comes ahead of next Thursday’s local elections, in which the Conservatives are predicted to lose up to 500 council seats.
It will pile further pressure on the prime minister, who already faces the threat of a potential challenge to his leadership from worried Tory MPs.
A Conservative Party spokesperson said: “For the people of Central Suffolk and North Ipswich this will be disappointing news.
“What Dan says is wrong as Sir Keir Starmer has no plan for our NHS. Under the Conservatives we are raising NHS funding to a record £165 billion a year, helping it recover from the effects of the pandemic and driving forward its first ever long term workforce plan so that we train the doctors and nurses we need for the future in our country.”