A Tory MP has defected from the Vote Leave campaign in favour of Remain in protest over claims made about the NHS.
Dr Sarah Wollaston, Commons Health Select Committee chairwoman, said the pro-Brexit claim that withdrawal from the EU would hand the NHS an extra £350 million a week was "untrue" .
And the Totnes MP said she was changing sides because she was not "comfortable" being part of a movement that used the wrong figures on its battle bus.
Dr Wollaston told the BBC: "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.
"If you're in a position where you can't hand out a Vote Leave leaflet, you can't be campaigning for that organisation."
Dr Wollaston warned there would be a "Brexit penalty" on the NHS as withdrawal would damage the economy.
"The consensus now is there would be a huge economic shock if we voted to leave. Undoubtedly, the thing that's most going to influence the financial health of the NHS is the background economy. So I think there would be a Brexit penalty."
Dr Wollaston stood by her decision to switch sides, insisting: "Nobody wants politicians who make the wrong decision."
Additional reporting by PA
