The NHS would be in "absolutely dire straits" without immigrant workers, an official at the Government spending watchdog has told MPs.
Office for Budget Responsibility (OBR) board member Stephen Nickell told the Treasury Select Committee that 35% of NHS workers are migrants.
"It's quite plain that, if they weren't there, the health service would be in absolutely dire straits," he said.
Mr Nickell also dismissed the idea that Britain was a "small island" that could not fit more people, saying: "There is masses of room. The urbanised part of Britain occupies less than 10% of the surface area."
"The urbanised part of Surrey occupies less of Surrey than golf courses. So in some senses, plenty of space."
As for the economic impact of migration, he said wages in certain sectors had been "held back" by migration, but "not [to] a massive extent".