New polling by Opinium on behalf of European Movement UK shows that, among British adults who felt Brexit had been harmful to the UK, more than three-quarters favoured the UK joining the Single Market and Customs Union as a way to lower the tax burden and boost money for public services.
The poll of 2060 UK adults was carried out between the 13th and 17th November.
The results come two days before Chancellor Rachel Reeves unveils her Autumn Budget - amid speculation that tax rises will be needed to bolster Britain's struggling economy.
Sir Nick Harvey, CEO of European Movement UK, said:
"We already know that leaving the European Union has severely damaged the UK economy. The Government's own watchdog, the OBR, has repeatedly said that it's already wiped billions off GDP.
"Rachel Reeves would be facing very different choices this week if the UK hadn't cut ties to its nearest and biggest trading partner. The red tape and uncertainty of the past 9 years have hit every single one of us in the pocket.
"Some estimates go further - a report this month from The National Bureau of Economic Research put the figure far higher, suggesting Brexit may have wiped as much as £240 billion off our GDP.
"Public opinion is now clear - our polling shows that the UK public know how to start repairing our economy, even if the Government hasn't caught up yet. Joining the Single Market and Customs Union would instantly boost our economic performance. Our challenge to the Chancellor is clear, you have admitted leaving the EU has been an economic disaster – so what tangible actions are you going to do to fix it?"
The full polling results can be downloaded here.