PARIS  A faltering auto giant whose brands are synonymous with the open road. Hundreds of thousands of unionized workers with powerful political backers. An urgent plea for the government to write a virtual blank check.

This is not the story of Ford and General Motors, but British Leyland, a car company that went through £11 billion of inflation-adjusted British taxpayer money, or $16.5 billion, in the ’70s and ’80s before going out of business. All that is left of the company now are memories of cars like the Triumph, and a painful lesson in the limited effectiveness of bailouts.

“It’s all too evocative,” said Leon Brittan, a top official in the government of Margaret Thatcher, the free-market-minded prime minister who nevertheless backed the rescue. “I’m not telling the U.S. what to do, but the lessons of the British experience is don’t throw good money after bad. British Leyland carried on for a few more years, but they’re not there now, are they?”

Other experts are sounding the same alarm. “The British Leyland experience is a relevant and cautionary one,” said John Casesa, a principal in the automotive consulting firm Casesa Shapiro Group in New York. “The government got in the business of trying to make a winner out of a structurally flawed company. That’s the risk in the U.S. as well.”