With just five months to go until the UK is due to leave the EU on March 29, voters now would back staying by 54% to 46%, the study by the Survation pollster for Channel 4 showed.
Prime Minister Theresa May has repeatedly ruled out a rerun of the referendum, though former prime ministers Tony Blair and John Major have called for another vote, and 700000 people marched in London last month to demand one.
British election expert John Curtice said the outcome of any new vote would still depend on who turned out. “The swing towards remain has been strongest among younger voters. It’s virtually absent among older voters.”
Previously, most opinion polls have shown only slight changes in public opinion since the Brexit vote.