26% of Leave supporters said it had gone worse than they expected, while 16% of those who voted for Brexit said they had expected it to go badly and had been proved right.
Among people who voted Remain, 86% said it had gone badly or worse than they expected. Overall, just 14% of all voters said Brexit had gone better than expected.
Adam Drummond, of Opinium, said the most striking finding was that Leavers were now more hesitant about the virtues of Brexit than previously.
Shane Brennan, chief executive of the Cold Chain Federation, said he expected many of the problems faced over the past year by small UK businesses exporting to the EU, particularly the rising cost of sending small amounts because of new charges, would now confront those sending small specialist consignments the other way, from the EU to the UK.
