“It’s hard to get them passionate about remaining,” said Scott Townsin, 26, who recently directed a campaign video urging young people to vote in favor of staying in the European Union.  Older voters tend to decide based on information they get from traditional media. But with young people, Mr. Townsin said, “you’ve got to be loud, you’ve got to compete with brands, favorite friends, Instagram, whatever, to get their attention.”  Britain will hold a referendum on June 23 on whether to leave the European Union, a decision nicknamed “Brexit.”  Zak Reynolds, 20, from London, said he had yet to make up his mind. One of his parents will vote to stay in, the other to leave.  “There’s a lot of propaganda stuff,” he said.  Sam Hemphill, 24, an engineering student from Swindon in southwest England, said he had not made up his mind but was leaning toward Britain’s remaining.  Part of his uncertainty, he said, was driven by the perception that the campaigns “are both lying.”  “All the facts and figures feel manipulated, which makes the decision hard,” he said. “They are both polar opposites appealing on emotions rather than facts.”  The In campaign used targeted Facebook ads to imply (falsely) that a British exit, or Brexit, could stop British soccer clubs from signing European players. (“If we leave the E.U., how will Tottenham be affected?” one ad asked.)  The Out campaign lent its support to a pop concert in Birmingham, only to have three acts pull out because they did not agree with its anti-Europe position.  The voter registration deadline was Thursday, prompting ambitious drives by both sides to sign up supporters.  Groups like Bite the Ballot, an organization that tries to encourage youths to vote, teamed up with Starbucks, which favors Britain’s remaining in the European Union, to hold registration drives in coffee shops across the country.  Uber, which has not taken a position on the referendum, flashed ads on customers’ smartphones reminding them to register.  Some surveys indicate that half of those between ages 18 and 30 want to remain in Europe, with the proportion higher among those under 25.  Young Britons are generally comfortable with a multicultural society, surveys have found, and they value the opportunity to work and travel in 28 European nations without a visa.  A survey released Tuesday by the Pew Research Center found that 57 percent of those 18 to 34 years old in Britain had a favorable view of the European Union, compared with 38 percent of people 50 and over.  The 180,000 or so people attending the five-day festival in Glastonbury will have to vote by mail — a relatively tedious process — or apply to have someone else vote on their behalf. (There will be no polling booths on the festival grounds, 900 acres of farmland in Somerset, since people have to vote where they are registered.)  The same voting rules apply to the 300,000 to 500,000 British fans, many of them under 30, who the police expect will travel to France for the monthlong European Soccer Championship.  Some of the efforts to get young people to vote are paying off.  Since March 1, more than a million people have registered to vote, with big gains among those 18 to 34 years old, according to figures published recently by the government.  Ashleigh Breedy, a 34-year-old florist in favor of Brexit, said the referendum was so important that she would vote for the very first time.  “All that money we’re sending to Belgium and them telling us what to do,” she said, referring to Brussels, where the European Commission is based.  “Our queen doesn’t have a say,” she said. “Is Belgium going to tell our queen what to do?” she asked, puffing on a cigarette and drinking a can of Red Bull. “If enough of us stand up to leave, we’ll leave.”  Brexit campaigners are calling for more controls on immigration and greater national sovereignty; the option of remaining is appealing to voters because of the economic benefits.  Charlie Carline, 31, a British exit supporter who will be in France on referendum day, said he had made sure to vote by mail.  It is “very important,” he wrote in a message on Facebook. “I want out of the European Union dictatorship. Look at the state of Europe because of these power-ridden scum leaders.”  By contrast, some of the young people supporting Britain’s continued membership in the European Union are less passionate. For them, the monthslong campaign often felt more like well-fed Conservative politicians arguing over a dining bill.  “It’s hard not to get bored by it,” said Josh Glancy, 29, who plans to go to Glastonbury and who applied for a postal vote only because a friend had insisted. “It’s a kind of spat among the Tory party, so I’ve become quite fed up with it.”  Still, he said he planned to vote to stay in Europe because he liked “the idea of a Europe that can cooperate” over issues including the migrant crisis.  Vahan Salorian, 23, who juggles work as a composer, primary school music teacher and pub supervisor, said he would vote for Britain to remain in Europe.  “I’ve been watching with mild terror” the possibility of a British exit, he said, wearing a T-shirt decorated with avocados and sipping beer with friends in a park in east London. “I’m terrified it might happen.”  Mr. Salorian, who is from the rural town of Barnoldswick in northern England, said living in a cosmopolitan city like London shaped his views. Friends in Barnoldswick, he said, were planning to vote out even though the area has had very little immigration.  Back in east London at the British Soap Awards, Jennifer Burnett, 33, said she was registered to vote, but was unsure about her intentions.  She had more definite views about the soaps. “I know exactly who I’m going to vote for,” she said. “Vote ‘Hollyoaks’!” she exclaimed, raising a plastic champagne cup in a celebratory gesture.  A version of this article appears in print on June 12, 2016, on page A1 of the New York edition with the headline: Young Britons Favor Staying in E.U. but Aren’t Big on Voting . Order Reprints| Today's Paper|Subscribe
Holding the attention of young voters — and getting them to turn out on June 23 for a referendum on whether Britain should stay in the European Union — is a challenge.