The Brexiteer pledge that quitting the European Union would boost NHS coffers by £350 million a week is coming back to bite them, according to pollsters.
Some 61 per cent of health workers now back remain compared to 39% who would vote to leave, according to research by YouGov for the People's Vote campaign.
It marks an increase in support for staying in the EU of 19 per cent since 2016.
In a referendum on a final deal, 65 per cent of nurses would vote to remain in the EU compared to 35 per cent, the study found.
Nearly eight in 10 doctors, 78 per cent, want a say on the outcome of the negotiations, with just six per cent opposed, the YouGov poll found.
Peter Kellner, a former president of YouGov, said: "The pledge at the heart of the Leave campaign two years ago is rebounding on the Brexiteers.
"Their promise to spend an extra £350 million a week on the NHS swayed not only voters as a whole; it prompted many NHS workers to vote Leave.
"Like the public as a whole, three in four NHS workers expect the pro-Brexit promise to be broken. But for them, this would be more than a general disappointment. It directly affects their own lives."
It comes as NHS staff attend a rally in central London calling for a fresh referendum.
A letter signed by nearly 8,000 healthcare workers calling for a vote has also been published.
It says Brexit is hitting staffing levels, will mean there is less money for funding and will hold back developments in medicine.
"The British people have been misled on what Brexit will mean for the NHS," it says.
"Far from £350 million more a week we are already seeing a staffing crisis and funding cuts - and that's before Brexit has even happened.
"New facts have come to light which show Brexit is already damaging the NHS. "
Dr Mike Galsworthy, founder of NHS against Brexit and a supporter of People's Vote campaign, said: "The pace is quickening now, as more and more NHS and health professionals are raising the alarm about Brexit.
"Brexit attacks the NHS from all sides. At NHS Against Brexit, we are now fighting back. We are demanding a People's Vote with the option to ditch Brexit entirely."
- YouGov surveyed 694 public sector health workers between July 31 and September 4 online.