U.K. Liberal Democrats Make Big Election Gains

He bungee jumped from 160 feet, rode a stomach-churning roller coaster, plunged down a water slide and toppled into a lake while attempting to paddleboard.

As leader of the Liberal Democrats, a small, centrist party, Ed Davey spared himself few indignities to secure news media coverage during a British election campaign dominated by bigger parties.

The appearances, alongside Mr. Davey’s heartfelt reflections on caring for his disabled son, have lifted his profile and that of the Lib Dems, who made significant advances in this election. The party won 71 seats, its best showing in a century, regaining its stature as the third largest party in Parliament.

As recently as the 2015 election, the party’s hold in Parliament had been reduced to eight seats.

In a statement, Mr. Davey, 58, said the striking reversal was the product of a “positive campaign with health and care at its heart.”

“I am humbled by the millions of people who backed us to both kick the Conservatives out of power and deliver the change our country needs,” Mr. Davey wrote on social media.

A significant driver of Lib Dem support seems to have come from voters in normally safe Conservative seats, who wanted to get the governing party out and found Mr. Davey’s centrist party more palatable than the center-left Labour Party.

The Lib Dems seized on the Conservatives’ vulnerability and challenged them in dozens of parliamentary constituencies, particularly in their southern England heartland. There, they sought to persuade supporters of other parties to lend their votes to a Lib Dem candidate to help defeat the Tory incumbent, a strategy that paid dividends.

Mr. Davey’s viral moments weren’t all stunts. In a moving social media post viewed more than 6.5 million times, Mr. Davey also shined a light on the lives of those caring for others by describing the challenges and rewards of looking after his disabled 16-year-old son.

Leading a party that made health and social care big priorities during the campaign, Mr. Davey also talked about his childhood — how his own father died when he was 4, leaving his mother to raise three boys under 10, until she was stricken with breast cancer just a few years later.

“My little brother and I nursed her until she died when I was 15, so I was a young carer,” he said in one interview.

It has been a long road back to political relevance for the Lib Dems, Britain’s most pro-European party, who are still recovering from their decision to enter a coalition government with the Conservatives in 2010, a time of steep spending cuts after the global financial crisis. The party enraged students by reneging on a pre-election promise to abolish tuition fees — instead increasing them — and was then punished by voters unhappy at reductions in public services.

In 2010, there were 57 Lib Dem members of Parliament. At the last general election, in 2019, the party won 11 seats.

Mr. Davey has come in for some criticism because he was a minister in the coalition government with the Conservatives during a devastating scandal in which hundreds of people who ran branches of the Post Office across Britain were wrongly accused of theft after a faulty IT system recorded shortfalls in their accounting.

The Lib Dem leader has since apologized for not doing more to investigate the scandal, saying he was sorry he “did not see through the Post Office’s lies.”