Six and a half years after voting to leave the European Union, three years after the formal departure, two years after signing a post-Brexit trade deal with Brussels and one month after installing its fourth prime minister since the 2016 referendum, Britain is caught in — what else? — another debate over Brexit.

Brexit may be in the history books, but “Bregret,” as the British newspapers have called it, is back in the air.

The cause of the remorse is clear: Britain’s economic crisis, which is the gravest in a generation and worse than those of its European neighbors. Not all — or even most — of the problems are because of Brexit, but Britain’s vexed trade relationship with the rest of Europe indisputably plays a role. That makes it a ripe target for an anxious public casting about for something to blame.

The latest eruption of this never-ending drama began last week with an opinion poll that showed support for Brexit had fallen to its lowest level yet. Only 32 percent of those surveyed in the poll, by the firm YouGov, said that they thought leaving the European Union was a good idea; 56 percent said it was a mistake.