The thorny question of the Irish border after Brexit was on the agenda when the Prime Minister met the Irish Taoiseach at a summit today. Mr Varadkar warned that a possible Brexit deal could collapse if Britain doesn’t say how it plans to keep the border open. And if a collapse led to a hard Brexit, could the outcome for Ireland be even more unexpected?

Channel 4 News has learned that some respected figures from the liberal wing of unionism are now ready to talk with the government in Dublin about Irish unity – and even a border poll.