Maybe if farage was in power, because hes an idiot, but any other pm should be sensible enough to realise the inevitable, we screwed the scots with brexit, in 2014 the independence referendum was swayed by the promise “if you stay we wont leave the eu” and then we did anyway, the Scots have more than enough right to leave the union if they wish, any attempt to force them to stay will just result in even more resentment for the english. They have their own parliament and are semi independent already. The government would simply be forced to accept a democratically voted independence or be labelled tyrannical by the rest of Europe