Right to leave: 41%
Wrong to leave: 47%
YouGov haven't provided figures with Don't Knows excluded, but it must be either a 53-47 or a 54-46 split, depending on how the rounding worked out. On the high side for Remain, yes, but hardly evidence of "rocketing".
So why were the results so different on the new question giving people a straight choice between Remain and May's deal? It's probably partly a "question ladder" effect. Before being asked that question, respondents were first asked whether they support or oppose the draft Brexit deal, and by a margin of almost 2-1 they said they were opposed. It would have been difficult for some people who are essentially Leave supporters to say they think the deal is awful one minute, and then say they would vote in favour of it the next minute. After all, several prominent Brexiteers have said that they would prefer to remain in the EU to leaving on the basis of the deal. But if it ever actually got to the point where there was a straight choice in a referendum between Remain and May's deal, it's safe to assume that almost all Brexiteers would get behind the deal (however grudgingly) and those numbers would in all likelihood start to look very different.
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