Jose Manuel Barroso said the bloc “will not get away with half-hearted solutions any more, and half-integrated institutions will no longer do”.
“We want to put all the elements on the table even if some of them may sound like political science fiction today,” he told a conference on the EU’s next steps. “They will be reality in a few years’ time.”
He argued that European states’ financial interdependence, as highlighted during the sovereign debt crisis, should be supported by closer political ties and a banking union.
His tone contrasted with that of Conservative MP Bernard Jenkin, who last night told Channel 4 News that failure to introduce a referendum on Britain’s continued membership of the EU would split the party and cause MPs to defect to Ukip.
Fellow Tory backbencher Jacob Rees-Mogg also suggested Ukip leader Nigel Farage could be a potential deputy prime minister in coalition with the Conservatives. Their discussions follow a declaration by former Conservative chancellor Lord Lawson that he would vote to leave the EU, saying it had become a “bureaucratic monstrosity”. Deputy PM Nick Clegg hit back, saying this would put British jobs at risk and leave the UK ostracised from the rest of the world.