August poll by the Bertelsmann Foundation shows 56% of Britons wanting to stay in the bloc.
Support for the EU has risen across Europe, including in the UK, since the British people voted to leave.
Pro-EU sentiment has grown in five of the six largest member states, according to a survey by the Bertelsmann Foundation. These were the UK, France, Germany, Poland and Italy. The only large state to see a fall in support for the EU was Spain.
“The looming Brexit seems to have been the best advertisement for the EU,” said Aart De Geus, of the Bertelsmann Foundation, Germany’s largest NGO.
In the UK referendum on 23 June, the country narrowly voted to leave the EU, with 52% voting leave while 48% supported remain.
But the Bertelsmann survey, completed in August against a backdrop of confusion about the British government’s Brexit strategy, showed that 56% of British citizens wanted to stay in the EU, compared with 49% when a similar survey was conducted in March.
According to the poll, enthusiasm for EU membership is slightly stronger in the UK than France or Italy where 53% and 51% respectively voiced approval. These figures were a modest rise from earlier in the year.
Support is strongest in Poland, the biggest beneficiary of European funds: the EU had a 77% approval rating in the latest poll, compared with 68% in March. Germany was in second place, with 69% expressing approval for the European project, up from 61%.
Support did slip in Spain, albeit from above-average levels: approval fell to 68% in August, down from 71%.
Across the EU as a whole, 62% want their state to remain a member, up from 57% in March. Researchers contacted more than 10,000 people in all EU countries.
The survey comes amid continuing uncertainty over Britain’s future status with the EU, with Theresa May’s government yet to express one view on whether the UK should remain in the single market or customs union.
With negotiations unlikely to begin before April 2017, the EU27 – the other 27 nations of the EU not including the UK – has been able to unite on the view that the UK cannot have access to the single market without accepting free movement of people.
Norbert Röttgen, chairman of the foreign affairs committee in the German Bundestag, told the Observer this weekend that he wanted to help the UK, but the British needed to be ready to compromise. He said: “I am really ready to come to a result but if [the British position is] no, no, no, then even I would have to say that there is no common ground.”