Dr Sarah Wollaston, a prominent Tory MP, has defected from the Brexit campaign and instead declared her support to remain in the EU.
Just over two weeks ahead of the referendum, the former GP, said that a vote to exit the EU would leave her feeling uncomfortable, as the claim that Brexit would free up £350 million a week for the NHS “simply isn’t true”.
In an interview with the BBC, Wollaston said: “For someone like me who has long campaigned for open and honest data in public life I could not have set foot on a battle bus that has at the heart of its campaign a figure that I know to be untrue.”
The Brexit campaign bus advertises that the UK sends £350m to Brussels every week.
Wollaston went on to explain in a blog post: “It's an empty promise and one, which would soon backfire.
“A strong economy has always been the cornerstone of funding for the NHS and for all the arguments about the scale of the economic turbulence, the clear consensus is that the effects would be significant and negative.
“Far from a leave dividend there would be an economic penalty and the NHS would suffer the consequences.”
In April, the UK Statistics Authority issued a letter, which also said the £350 million figure could be misleading as it fails to account for the rebate from the EU to the UK public sector or non-public sector bodies.
She adds that the effect of a Brexit would have further implication for the NHS workforce.
She said: “If you meet a migrant in the NHS, they are more likely to be treating you than ahead of you in the queue and very many of our core health and social care workforce come from the EU.”
The MP for Totnes also added that the UK benefits from the EU’s role in responding to health threats as well as their role in promoting good water and air quality, “which are no respecters of national boundaries”.
She said: “I came into politics to campaign on health so I've listened carefully to the evidence from both sides on this. The claims about health from the leave campaign have been shameful.”
The change of heart comes four months after backing Brexit in February.
At the time she said on her blog: “So why am I heading towards the door? I am in love with the possibilities of the EU but can no longer ignore the grinding reality of the institution.”
Prime Minister David Cameron tweeted that Wollaston’s decision is a “powerful intervention” for Remain voters.