With a week to go before the momentous decision on the future of the UK in the EU the polls show a narrow but consistent lead for Brexit.

The Remain campaign believes they have won the intellectual argument but the Leave campaign considers they have won the emotional argument and the battle in social media. ‘Take Back Control’ has been an effective slogan.

Leave has emphasised the immigration argument and the cost of British membership arguing that the UK economy, free of Brussels red tape, would flourish after a period of adjustment. Boris Johnson has been the de facto leader of the Leave campaign hoping that it will provide a path for him to become prime minister.

Remain has stuck to the dangers to the economy following a Brexit. Continuing the Remain campaign’s Project Fear, finance minister George Osborne has warned of the need for an emergency budget with tax rises and budget cuts in the event of a Brexit. The shock of a possible Brexit has sent shudders through global stock markets and a slide in sterling prompting the Financial Times to write about ‘an unnecessary referendum with devastating consequences.’

There now appears little chance of a clear victory for either side and so David Cameron’s hope of finally putting the EU issue to bed will not be realised. The Euro-poison that has infected the British political system will not be eradicated after 23 June.

In the event of a narrow Remain victory the 150 plus Eurosceptic MPs are not going to make life easy for the government, assuming Cameron can stitch his party together again. The UK will continue to be an awkward semi-detached member of the EU blocking proposals for further integration.

In the event of a narrow Leave victory there are a multitude of unknowns. Will there be a ‘hard Brexit’ as hinted by German finance minister Wolfgang Schäuble or a ‘soft Brexit’ as argued by Boris Johnson? What kind of deal will there be with the EU and in what timeframe? What kind of other trade deals will be negotiated and in what timeframe? Will the UK still be at ‘the back of the queue’ if Trump is in the White House?

But the fall out for the UK political system is perhaps the biggest unknown. A referendum has no constitutional standing in the UK. What if, as is likely, Scotland votes heavily to remain while England votes to leave? Would the 50 Scottish MPs at Westminster support a Brexit bill? Indeed how many MPs overall would support a bill to pull the UK out of the EU without any alternative in place? The vast majority of MPs want the UK to remain in the Single Market but this would not be possible without accepting the free movement of labour.

And who will be in charge? Win or lose Cameron is likely to face a leadership challenge. Many think that he will have to resign if he loses. In most countries a defeat might also trigger an election. But this is now very difficult as the UK has fixed five year parliaments and an election can only be called if there is a vote of no confidence in the government. Neither the Conservatives nor Labour would wish an election in the current circumstances.

So could Boris make it to Number Ten? It is by no means certain that he would win a leadership election. The quiet money is on Theresa May who has been noticeably absent from the campaign and who could emerge as the unity candidate.

Whatever the outcome next week the EU issue, famously described by the late Guardian commentator, Hugo Young, as This Blessed Plot, will not go away in British politics. It may require twenty years of Britain outside the EU and another generation of politicians to take over before the boil is finally lanced. And perhaps when the UK re-joins in 2036 it might become a full member of the EU.