A generation of young Britons who were locked out of the 2016 EU referendum because of their age now believe that Brexit has failed, with a majority demanding a fresh vote to rejoin the EU, exclusive polling shows.

Gen Z Britons show deep dissatisfaction with the UK’s departure from the EU, according to new polling of 18- to 28-year-olds conducted by the thinktank More in Common and shared with the Guardian.

The data reveals that 60% of this cohort would vote to rejoin the bloc if given the opportunity, compared with 9% who would vote to stay out.

When filtering the results to focus solely on those likely to cast a ballot in a hypothetical second referendum, the margin becomes a landslide, with the pro-EU Remain/Rejoin camp capturing 81% of the vote against just 19% for remaining outside.

The More in Common study, which surveyed 440 young people across Britain, shows that 50% of gen Z Britons categorise Brexit as a failure. In contrast, only 16% view the project as a success, while 34% remain undecided.

Luke Tryl, the executive director of More In Common, said: “For many gen Z Britons, the Brexit referendum was formative to their political ‘coming of age’. In focus groups, many in this age group say Brexit was the first political event they were vividly aware of – too young to vote, but with distinct memories of that campaign and the years of debate that followed.

“Ten years on, our polling of Britons aged 18 to 28 reveals how they feel about Brexit: they tend to believe it has failed, and three in five want a fresh referendum on rejoining. But interestingly, few think the principle of Brexit was doomed from the start – like the rest of the public, they tend to say it could have worked well, but that politicians ruined it.

“And while young Britons mostly support rejoining in principle, focus group conversations with gen Z voters suggest they’re hesitant about a return to the endless Brexit debates they remember from their youth, which risks distracting from the issues they care most about – the cost of living, affordable housing, jobs and climate change.”

Hostility toward the UK’s exit from the EU is strongest among the youngest adults. Among those aged 18 to 21 – who were children aged six to nine in 2016 – 53% declare Brexit a failure, while only 12% see it as a success. This sentiment softens slightly among older gen Zers aged 25 to 28, though the outlook remains negative at 48% failure to 20% success.

While there is a consensus that the current state of affairs is not working, young Britons are divided on whether the project was flawed conceptually or butchered by the political class. About 37% believe Brexit could have worked well but was “ruined by politicians” who handled it badly, while 29% argue that the project was “never going to work” from the very beginning.

Only 11% maintain that Brexit has worked well so far, and 23% expressed no opinion.

The polling arrives amid a broader national conversation regarding the demographic transformation of the UK electorate. The narrow 2016 referendum result – won by Leave with 51.9% to Remain’s 48.1% – was heavily carried by older generations.

However, time has altered the voter rolls significantly. The pollster Peter Kellner has argued that the pro-Brexit majority in 2016 has gone. Writing on Substack, he noted that more than 6 million Britons have died since the 2016 referendum, and argued that because older demographics voted overwhelmingly to leave the EU – 64% of those over 65 voted to leave – mortality has disproportionately affected the leave coalition.

According to calculations based on Office for National Statistics data and published by the Financial Times, roughly 15% of original Leave voters have died, compared with 10% of Remain voters.

Meanwhile, about 6 million young people who were ineligible in 2016 have aged into the electorate. This generational replacement has led analysts to argue that the pro-Brexit majority has in effect vanished through natural population turnover, creating an active “anti-Brexit” majority of several million living voters.

According to the More in Common polling, three in five young Britons – 62% – said that there should be a referendum on rejoining the EU within the next five years. Only 11% of under-29s oppose holding another vote, while 27% are unsure.

The appetite for a second referendum is highest among those who wish to return to the European fold, with 88% of prospective Rejoin voters backing a new ballot.