LONDON — One by one, the pubs are disappearing in Hampstead, a jewel-box village of cobbled lanes and Georgian homes that has become one of this city’s most fashionable neighborhoods. The Nags Head has become a realty office. The King of Bohemia is now a clothing shop. The Hare & Hounds has been replaced with an apartment building.

Changing economics and shifting tastes have claimed roughly one out of every five pubs during the last two decades in Britain, and things are growing worse. Since the 2008 financial crisis, 7,000 have shut, leaving some small communities confronting unthinkable: life without a “local,” as pubs are known.

And that has spurred the government into action. New legislation is letting people petition to have a pub designated an “asset of community value,” a status that provides a degree of protection from demolition and helps community groups buy pubs themselves, rather than seeing them get snatched up by real estate developers eager to convert them for other uses or tear them down. Since the Ivy House, a beloved local in south London, became the first to receive the designation last year, roughly 300 others have followed suit.

“The pub, we like to think, is relatively internationally unique, it’s a very traditional thing,” said Brandon Lewis, the Conservative member of Parliament who is the Community Pubs Minister, an office that underscores the special place pubs occupy in British life. “In many communities they are really important, not just because it’s where people come together, but it will be the focal point for fund-raising for the community, for the local football club, for the dance class, for the moms’ coffee morning.”