LONDON — Britons love to mock their National Health Service — just don’t let anyone else poke fun at it.

They particularly resent the British universal health care system being used as a punching bag in the battle against President Barack Obama’s proposed reforms.

Conservatives in the United States have relied on horror stories from Britain’s system to warn Americans that Obama is trying to impose a socialized health care system that would give the government too much power.

In an interview widely interpreted here as an attack on the U.K., Republican Senator Chuck Grassley of Iowa told a local radio station last week that “countries that have government-run health care” would not have given Sen. Edward Kennedy, who suffers from a brain tumor, the same standard of care as in the U.S. because he is too old.

The superheated debate broadened this week to include renowned physicist Stephen Hawking, a British icon who suffers from motor neurone disease. A U.S. newspaper wrote that under the British system Hawking would be allowed to die — an assertion that Hawking said was absurd.

“I wouldn’t be here today if it were not for the NHS,” Hawking said, joining the ranks of those praising Britain’s system.

Britons say the country’s universal health care system, which provides free medical care, is far fairer than the current American system.

Behind the criticism is a popular British view that American society represents unbridled capitalism run amok, with catastrophic results for people left behind in the boom times like those of the last two decades.

Business Secretary Peter Mandelson, who is usually pro-American, blasted U.S. health care Friday, suggesting the delivery system is fine for the wealthy but not for the poor.

“If you can’t pay, you have a very, very second-rate service or you can’t get health service at all,” he said.

Britain’s left-leaning government has responded to criticism offering selected statistics that show England out performing the U.S. in health spending per capita, life expectancy and more.

Newspapers have jumped in, with the Daily Mirror calling the United States “the land of the fee” because of the way patients are forced to pay for medical services.

And Dr. Hamish Meldrum, chairman of the British Medical Association, warned Friday that Britain must be careful not to let America’s “market-style philosophy” take hold at the NHS.

The National Health Service, one of the world’s largest publicly funded health services, was set up in 1949 with the intention of providing everyone with access to health care regardless of their ability to pay. A number of other countries, including Canada, have similar systems.

Despite the widespread show of support for the British system recently, the NHS has been struggling to cope with rising medical costs, and there are fears it could be overwhelmed if swine flu cases surge this winter.

Doctors and nurses warn that the organization faces a $24 billion deficit, and NHS hospitals are often overcrowded, dirty and understaffed. Many people have to wait weeks or months for medical care despite government promises to shorten waiting lists.

But even those who complain about the NHS say they want it to be improved, not dismantled or transformed into a U.S.-style, profit-oriented system.

Generations of Britons have grown up with universal coverage and although about 12 percent of the population has private insurance, the vast majority of people still rely on the system to provide them with emergency care, surgery, and access to a family doctor.

“The NHS has many faults but health care is a basic right and shouldn’t be an arena for private companies to make profit,” said Kathryn Wilson, an information technology consultant.