Boris Johnson has been confronted by sceptical nurses while campaigning in a hospital over his pledge to boost their ranks in the NHS by tens of thousands.

“Do you have a nurses tree too?” one nurse inquired, as the prime minister outlined his plans to add 50,000 nurses at West Cornwall Hospital.

The pledge, announced as part of the Tory manifesto on Sunday, immediately became embroiled in controversy when it became clear it included 18,500 nurses who already work in the NHS.

Mr Johnson to staff at the Penzance hospital that the plan was “fully costed”, but one probed again: “Where are these people going to come from?”

ITV showed the PM facing the interrogation over a cup of tea during the face-to-face meeting with medical staff on the campaign trail.

NHS at 70: demonstration and celebration march to mark anniversary Show all 18 1 /18 NHS at 70: demonstration and celebration march to mark anniversary NHS at 70: demonstration and celebration march to mark anniversary People holding placards attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary Labour Party leader, Jeremy Corbyn, addresses demonstrators following the march AFP/Getty NHS at 70: demonstration and celebration march to mark anniversary A man stands with a coffin, used as a prop at a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary epa06851663 Thousands of people march, to mark 70 years of the British National Health Service (NHS), in central London, Britain, 30 June 2018. Reports state that the gathering is calling on the government for increased funding and staffing for the NHS, as well as a protest against privatisation of an organisation which turns 70 years old on 05 July 2018. EPA/ANDY RAIN ANDY RAIN EPA NHS at 70: demonstration and celebration march to mark anniversary People holding placards attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary A man wears an NHS themed hat during a march in support of the National Health Service, in central London, Britain, June 30, 2018. REUTERS/Simon Dawson SIMON DAWSON Reuters NHS at 70: demonstration and celebration march to mark anniversary Demonstrators hold placards during a march in support of the National Health Service, in central London, Britain, June 30, 2018. REUTERS/Simon Dawson SIMON DAWSON REUTERS NHS at 70: demonstration and celebration march to mark anniversary epa06851662 A man with a birthday placard as thousands of people march, to mark 70 years of the British National Health Service (NHS), in central London, Britain, 30 June 2018. Reports state that the gathering is calling on the government for increased funding and staffing for the NHS, as well as a protest against privatisation of an organisation which turns 70 years old on 05 July 2018. EPA/ANDY RAIN ANDY RAIN EPA NHS at 70: demonstration and celebration march to mark anniversary Demonstrators stand in Whitehall during a march in support of the National Health Service, in central London, Britain, June 30, 2018. REUTERS/Simon Dawson SIMON DAWSON REUTERS NHS at 70: demonstration and celebration march to mark anniversary People march in central London to mark the 70th anniversary of the NHS. PRESS ASSOCIATION Photo. Picture date: Saturday June 30, 2018. See PA story INDUSTRY Demonstration. Photo credit should read: John Stillwell/PA Wire John Stillwell PA NHS at 70: demonstration and celebration march to mark anniversary Demonstrators hold placards during of a march in support of the National Health Service, in central London, Britain, June 30, 2018. REUTERS/Simon Dawson SIMON DAWSON REUTERS NHS at 70: demonstration and celebration march to mark anniversary People holding placards attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary Demonstrators hold placards during a march in support of the National Health Service, in central London, Britain, June 30, 2018. REUTERS/Simon Dawson SIMON DAWSON REUTERS NHS at 70: demonstration and celebration march to mark anniversary Jeremy Corbyn and Jon Ashworth speak during a march in central London, marking the 70th anniversary of the NHS. PRESS ASSOCIATION Photo. Picture date: Saturday June 30, 2018. See PA story INDUSTRY Demonstration. Photo credit should read: John Stillwell/PA Wire John Stillwell PA NHS at 70: demonstration and celebration march to mark anniversary People holding placards attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary People holding placards attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary People gather with placards to attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images NHS at 70: demonstration and celebration march to mark anniversary People gather with placards to attend a demonstration and celebration march to mark the 70th anniversary of the National Health Service (NHS), in central London on June 30, 2018. Organised by the Peoples Assembly, Health Campaigns Together, The TUC and 11 other health trade unions, tens of thousands are expected to attend the only national public event organised to mark the anniversary of the British Health Service. / AFP PHOTO / Tolga AKMENTOLGA AKMEN/AFP/Getty Images TOLGA AKMEN AFP/Getty Images

He said he hoped to fill the recruitment drive with people who have grown up in the UK, but "we’ve also got to make sure we are open to people from around the world”.

Twitter users were quick to note the nurses’ body language during the short exchange. “They don’t look convinced,” said one. Another replied: “Her face says it all.”

One woman also told the prime minister she was a student nurse and struggling financially.

When Mr Johnson reinstated his plans to bring back the nursing bursary, she pressed him on tuition fees.

Nurse asks Boris Johnson to reduce tuition fees

“I’ll have to check that,” he said.

At the manifesto launch, the prime minister said his government would reintroduce maintenance grants, which were scrapped in 2017.