The head of the NHS has called on the Government to assure its foreign staff that their jobs are safe post-Brexit.
Laying out a blueprint for Britain's health service outside the European Union, Simon Stevens said it will continue to be reliant on professionals from abroad in spite of initiatives to increase the number of NHS workers from the UK.
Mr Stevens, chief executive of NHS England, called on Theresa May to institute "bold and broad reforms" that include protecting the rights of Europeans working in hospitals and surgeries across the country.
Before taking office the new Prime Minister said she would not guarantee that EU nationals living in the UK could stay and seek action on free movement.
Writing in the Daily Telegraph Mr Stevens warned that attempts to curb immigration could trigger the closure of hospitals and care homes that have relied on nearly 130,000 European nurses, doctors and other staff for years.
He said: "As the largest employer in Europe, the NHS needs to do a better job training and looking after staff.
"New apprenticeships can help many 'left-behind' communities alienated from modern Britain. Even then we're still going to need committed professionals from abroad.
"Australian-style immigration points systems all admit nurses, doctors and other skilled experts. It should be uncontroversial to provide early reassurance to foreign NHS employees about their continued welcome."
Mr Stevens said the NHS also faces major challenges from childhood obesity, access to GPs, falling capital investment and inefficiencies.
Allowing childhood obesity to go unchecked will cost the NHS billions in future, while poor diet is now the biggest avoidable cause of ill health.
The Government needed to "urgently" draw up an "activist child obesity strategy" with comprehensive action on promotions and advertising, he said.
Meanwhile the provision of care across the NHS needs a "major overhaul", with access to GPs at its heart, Mr Stevens said.
He also repeated concerns raised by Mrs May that mental health is the "poor relation" to other conditions.
Mr Stevens called on the Department of Health to borrow to improve services.
He said attempts to meet running costs by diverting money away from capital investment meant many patients were going to appointments in "overcrowded and clapped-out buildings in need of a makeover, if not a bulldozer".
Mr Stevens said: "The need for radical change is now. We know what needs doing. Let's get on with it."
The remarks by Mr Stevens about foreign NHS workers come after Clare Marx, president of the Royal College of Surgeons, said Brexit could lead to improved patient safety by allowing health bosses to "seize the moment" and toughen up English language entry tests for staff.