Philip Johnston:

But it will be up to the Commons, with its pro-EU majority, to sort out which laws we keep and reject

Here is a confident prediction about the outcome of the EU referendum on June 23. The first result, to be declared at around 1 am, will be overwhelmingly in favour of staying in. There will be an 85 per cent turnout – and 88 per cent of voters, or thereabouts, will be for Remain. But since we are talking about Gibraltar, where the polls will close an hour earlier than here and just 22,000-odd votes need to be counted, it will tell us nothing about what is to come next. The latest polls suggest that the Gibraltarians and the rest of us now seriously need to contemplate the prospect that Leave is going to win.

I have been abroad for the past few weeks, behind the Great Firewall of China and mercifully shielded from the day-to-day arguments of the various camps. I had expected to come home to find Remain firmly in the driving seat, Project Fear having done its worst, but far from it. The most recent polls show a marked shift towards Leave. As Sir Lynton Crosby, the political strategist, wrote in this newspaper yesterday, the Leave campaign is narrowing the gap among those certain to vote. “The clear trend over the course of ORB’s polls for The

Daily Telegraph shows that the Leave campaign has a turnout advantage over the Remain campaign. If this persists to June 23, the referendum could come down to the wire,” he said.

On Monday, I went to see an old political friend, a sometime adviser to Downing Street who follows the polls more closely than most and has a reputation for accurately calling election results, both national and local. He is for staying in the EU but told me: “On the balance of probabilities, unless there is a big development over the next two weeks, then Leave will win.” Another old acquaintance, an ardent Eurosceptic, reported how MPs supporting Remain are steeped in gloom having been back to their constituencies over the short recess and spoken to voters. Leavers, by contrast, were buoyed up by their conversations. The worm has turned.

It feels like that moment some 10 days before the Scottish independence referendum two years ago when a YouGov poll showed the separatists ahead for the first (and only) time. There was panic among the pro-Union camp and a promise was made of further devolution – the so-called Vow. Whether this was enough to pull the Scots back from independence or whether the poll was a rogue and No was always going to win we can never be sure. But this time there is not going to be a similar deus ex machina unless the EU’s Five Presidents (I shall award a prize to anyone who can name them all) get together and offer the UK the sort of deal they should have given David Cameron in the first place.

Proper consideration, therefore, needs to be given to what happens in the event of a vote to Leave. Whitehall and the Bank of England have made contingency plans for what to do in the immediate aftermath to offset shocks on the financial markets – or at least, they should have done.

Politically, there will be turmoil. Mr Cameron may be forced out of Downing Street; the EU will call an emergency summit to reassert its intention to hold the institution together; and across Europe, most people will settle down to watch the football.

Then what? Leavers fear Mr Cameron will trigger Article 50 of the Lisbon Treaty immediately, setting a two-year timetable to negotiate an exit. The Prime Minister said as much recently in the Commons, though having just lost the referendum, he may not be in a position to do so. Once notice to withdraw is given, agreement is arrived at by qualified majority voting among the remaining members, effectively taking control of events away from Britain.

Leavers want a more measured response. “We will need to put the whole thing in suspension while everyone calms down,” one prominent Eurosceptic says. There is nothing to stop Britain declaring unilateral independence once the European Communities Act – the legislation that took us into the Common Market more than 40 years ago – has been repealed. Under Article 50 only the EU is obliged to seek a negotiation, not the withdrawing member state.

Everything will depend on how Parliament responds. After all, the essence of this debate is about restoring parliamentary sovereignty. It will be for MPs to decide. The problem, however, is that there is a pro-EU majority in the Commons; and while they will not spurn the will of the people expressed in the referendum, the method of our withdrawal – should that be the outcome – will be in their hands.

Stephen Kinnock, Labour MP for Aberavon, caused consternation among Leavers when he suggested that there could be a vote to remain in the single market – to leave the EU but retain a trading relationship along the lines of Switzerland. This would require us to go on granting open access to the British labour market for all EU citizens. But since the Leave campaign appears to have been given a boost by focusing on immigration, would Parliament not then be ignoring the wishes of voters?

Constitutionally, Mr Kinnock is right. He is further aided by the fact that until relatively recently, the Leave campaign was open to the idea of a Swiss-style deal with the EU, before realising that staying in the single market would make it impossible to play the immigration card. But if this referendum is about “taking back control” then the only place where that control can be exercised is in Parliament. We don’t have mob rule.

One way of doing this is for a Bill to be introduced to repeal the European Communities Act and deem all other EU laws to have been passed under the UK legislation that implemented it. Existing directives and rules would stay in force – but under the authority of Parliament, not the EU. Negotiations could then take place to decide which trading agreements would stay and which would go. On everything else, such as border controls, VAT and benefits, Britain would make its own decisions. But since there is a pro-EU majority in the Commons, the wishes of the Leavers could always be overridden without a further mandate from the people setting out precisely what Britain’s post-EU arrangements should be. That might need an early general election to sort out.