Nearly two years after Britons voted in favor of the U.K. leaving the European Union, some are calling for a second Brexit referendum. This time, however, the question isn’t whether the U.K. should leave the bloc, but how.

Concern over what kind of final deal the U.K. will get out of its negotiations with the EU has fueled the recent interest in a second referendum. A survey published Friday by the Guardian and British pollster ICM found that 47 percent of British voters surveyed support having a say on the terms of a final Brexit deal. When one omits the respondents who said they were undecided, support jumps to 58 percent. And the support comes from voters on both sides of the Brexit debate: The poll estimates that one quarter of “leave” voters also favor having a second referendum on the final deal.

The debate over the type of final deal the U.K. should seek is almost as fraught as the one over whether it should leave the bloc at all. Some, like London Mayor Sadiq Khan, have called for a final deal that allows the U.K. to remain within the EU’s single market and customs union, while others, like British Trade Secretary Liam Fox, adamantly oppose the U.K. staying in either. The debate is made no less contentious by revelations that all plausible Brexit scenarios—including those in which the U.K. stays in the single market, those in which it leaves the single market (but with a free-trade agreement with the EU), and a hard Brexit (leaving the single market without a deal)—appear to leave the U.K. worse off than it is currently. A leaked Brexit impact report prepared by the British government found that, in all plausible scenarios, almost every sector of the U.K. economy would take a hit.

Polling has shown that if the U.K. were to put the original Brexit referendum to a re-vote, the outcome would closely mirror the first outcome, albeit with reversed results: 51 percent are projected to support remaining in the EU, with 49 percent in favor of leaving it. This is likely due, at least in part, to the fact that the demographic divides surrounding the Brexit debate have remained consistent. Voters under the age of 24 are still more likely to want to remain, and voters over the age of 65 are just as determined to leave.

In fact, a new report by the independent London-based research institute U.K. in a Changing Europe found that one consequence of Brexit has been the creation of two new, and seemingly unyielding, political identities: Leavers and Remainers. “And one thing we know about identities is that they do not easily shift,” the report reads. “Eighteen months on from the referendum, its effects on our politics show no sign of dissipating. … There is thus little evidence to support the Prime Minister’s statement that Britain ‘has come together’ to face the challenge of Brexit. It seems that she is presiding over a divided and polarized nation.”

Complicating matters, those expressing interest in a second referendum are probably interpreting what that means differently, depending on whichever final Brexit outcome they favor. “Remainers are thinking about a referendum that gives you a choice between Theresa May’s deal and staying in the European Union,” Anand Menon, the director of U.K. in a Changing Europe, told me. “Some people are thinking if we have a referendum, it should be between Theresa May’s deal and leaving with no deal at all. And other people seem to think that having a vote on the deal means you have three or four options on a menu for sorts of deals you can have with the EU and you pick one, which obviously isn’t possible because she will have negotiated a single deal by then.”

The British parliament is one group that will be guaranteed a final say on whatever divorce terms U.K. negotiators agree to with the EU. In December, the parliament backed an amendment to the EU withdrawal bill that codifies British lawmakers’ right to reject the terms of the agreement and send both sides back to the negotiating table. Menon notes, however, that the British government might not have the luxury of that kind of time. “A vote in October isn’t a meaningful vote because it’s too late for parliament to actually amend the terms that are negotiated,” he said. “So the choice is basically have this deal or have no deal.”