Public buildings were floodlit in medical blue and prayers were said at Westminster Abbey to celebrate the state-funded service, launched on July 5, 1948, in a country determined to build a fairer society out of the ruins of war.
The NHS principle of free medical treatment, funded by taxation, retains wide support. But it has been challenged by rising life expectancy, increasing patient expectations and the vagaries of government funding.
"In poll after poll, if you ask British people what makes them most proud to be British, they say it is the NHS," said Health Secretary Jeremy Hunt — a member of the Conservative government that opponents accuse of starving the health service of funds.
Since a Conservative-led government introduced public spending cuts in 2010 in the wake of the global financial crisis, NHS funding has grown by about 1 percent a year. But demand is growing by some 4 percent, as the British population grows both larger and older.
After a spike in ambulance delays and canceled operations this winter, Prime Minister Theresa May last month announced the service would receive 20.5 billion pounds ($27 billion) in extra funding by 2023-24, a 3.4 percent annual rise in real terms.
The birthday was marked by an outpouring of affection and reflection, for a gigantic institution that employs more than 1 million people and helped shape the way Britain thinks about itself. The BBC devoted hours of TV and radio programming to the anniversary, including a reality series in which celebrities went to work in hospitals. It broadcast a specially commissioned symphony that featured bleeps, pings and assorted other hospital sounds.
Tea parties were held across the country Thursday to raise funds for NHS-linked charities. On a Welsh mountainside, artist Nathan Wyburn created a giant portrait of postwar health minister Aneurin Bevin, father of the NHS.
Roberta Bivins, a professor of history of medicine at the University of Warwick, said the NHS was "part of the national myth of self" in Britain, embodying cherished values of equality and fair play. "The negative side of the picture is that since 1949 politicians have been saying that the NHS is in crisis and using it as a political football," said Bivins.
In recent years the NHS has become ammunition in Britain's debate about the European Union. Before the 2016 referendum on EU membership, the "leave" campaign plastered a bus with the eye-catching — and inaccurate — claim that Britain sends the EU 350 million pounds ($460 million) a week that could, once the U.K. leaves, go to the NHS.
The net figure Britain sends is about half that much, and many economists say leaving the EU will harm the economy and squeeze public funding. Brexit, which will end the automatic right of EU citizens to live in Britain, also threatens the status of European workers who make up a big chunk of NHS staff.
A recent study by a group of health and economic think tanks found that the NHS provided good value for the amount of money spent on it, but had worse outcomes than comparable countries for some serious diseases, including several forms of cancer.
"The truth about the NHS is that by international standards it is a perfectly ordinary health care system, providing average levels of care for a middling level of cost," said Paul Johnson, director of the Institute for Fiscal Studies.
Britons don't hesitate to criticize the health service — but nothing unites the country like an outsider doing it. When U.S. President Donald Trump tweeted in February that the NHS was "going broke and not working," he drew a rebuke from the British government.
Hunt, the health secretary, retorted: "NHS may have challenges but I'm proud to be from the country that invented universal coverage - where all get care no matter the size of their bank balance."