An American trade deal raises the prospect of more private involvement in British health care

AS BRITAIN considers its future outside the European Union, its main target for a post-Brexit trade deal is the United States. The prospect of opening up the American market is an enticing one. Yet some in Britain worry about what might be demanded in return. Perhaps most emotive is the suggestion that America could negotiate greater access for its companies to the National Health Service. Jonathan Ashworth, the shadow health secretary, has warned that a trade deal could lead to “stealth privatisation” of the NHS. “It is beyond belief that our prime minister is bartering away our health service in her desperation for post-Brexit trade deals,” he recently said.

Private involvement in public health care has been growing in Britain for some time. After 1997 Tony Blair encouraged private providers to take on more NHS work, to help the service cope with increasing demand. That trend has continued. Government funding to the private sector reached £8.7bn ($11bn) in 2016, or 7.6% of the NHS’s total revenue budget.

Almost all American investment in British health care so far has been in the private sector, through acquisitions...