Former minister and Conservative MP Dan Poulter has defected to Labour.
In an exclusive TV interview with the BBC, the MP for Central Suffolk and North Ipswich told Sunday with Laura Kuenssberg that he could no longer look his NHS colleagues and patients in the eye and stay on as a Conservative.
Dr Poulter, who works part time as a doctor, said that Conservatives were no longer focused on public services.
Downing Street has just been told of his decision and is yet to respond.
Dr Poulter said he would sit as a Labour MP until the general election and then stand down.
He said: "I found it increasingly difficult to look my NHS colleagues in the eye, my patients in the eye, and my constituents in the eye with good conscience."
He suggested the party had stopped valuing public services, saying: "The difficulty for the Conservative Party is that the party I was elected into valued public services… it had a compassionate view about supporting the more disadvantaged in society.
"I think the Conservative Party today is in a very different place."
Dr Poulter, who was first elected in 2010, served as a health minister for several years under the coalition.
He said he had "no animus" towards Prime Minister Rishi Sunak but that the country needed a general election as soon as possible, adding that Labour and Sir Keir Starmer could be trusted to run the NHS and the country.
Asked if his constituents who elected him as a Conservative would be angry with his decision he said: "I could have carried on to the election and then stood down, or I could have decided to call a by-election… and I thought on balance, because there's going to be an election very soon, it's better to work for my constituents through to the end of this Parliament."
It is only the third Conservative defection since 2019.
Lee Anderson who sat briefly as an independent joined Reform last month. Christian Wakeford left the Conservatives for the Labour Party in 2022.