James Cartlidge is MP for South Suffolk.

One word summarises the Brexit cause more than any other: sovereignty. Self-Government and self-determination all rolled into one powerful, timeless concept that fires up the pro-Leave believers with fervour for quitting the EU as a policy end in itself. It’s about breaking Brussels’ shackles – but crucial to this argument is not only that we are subjugated to a supranational power, but to one which is failing.

As Douglas Carswell put it when a Conservative MP: “Far from joining an economic powerhouse, we’ve shackled ourselves to a corpse”. It’s therefore worth asking what the following EU states have in common: Luxembourg; Ireland; Netherlands; Austria; Germany; Sweden; Denmark; Belgium and Finland. Answer: according to the World Bank, by GDP per capita the people in every one of those countries are wealthier than the people of the UK, often significantly so.

Some corpse.

In fact, in the IMF global list of GDP per capita, France is one place above us (with positions reversed on the World Bank list). We are 27th overall, performing as badly as in recent Eurovision contests. Italy and Spain are 32nd and 33rd.  We are therefore significantly closer to the ‘basket case’ southern EU nations than we are to the Netherlands, a trading titan we should be emulating. It is true that both lists include wealthy non-EU Single Market members Norway, Iceland and Switzerland well above us. But Leave campaigners are not suggesting we emulate their models.

To be clear, lamenting our relatively low GDP per capita standing is not to call into question our economic performance since 2010, which has been extremely impressive in terms of job creation, deficit reduction and restoring growth. I am proud of our Government’s economic record. Rather, the IMF data highlights another of those long-standing structural failings in our economy, along with productivity and the trade deficit, which have persisted for many years under all governments. The Brexit answer to every question on what Leave looks like may be: “relax – we are the world’s fifth largest economy”, but we have debts to match, which is what makes us so vulnerable. I will vote for Remain not because I dismiss the pure sovereignty of law, but because I believe it is trumped by the tangible sovereignty of economic strength that is the true arbiter of power for people and those who govern them.

It is a profound irony that Brexiteers tend to talk of the decline of the EU in aggregate, choosing to speak in supra-national terms when it suits them, rather than recognising that within the whole are some of the world’s most dynamic economies. But regardless of what form the EU corpus takes – whether full of life or bordering on expiry – surely we are nevertheless ‘shackled’ to it in an irrefutable affront to our national sovereignty?

Remain supporters have tended to dismiss the sovereignty argument in terms of the ‘illusory’ nature of such power, arguing that were we to ‘do a Norway’ we would become an EU rule-taker rather than rule-marker. But I would go further than that, and challenge the nature of sovereign power as it matters in the real world. To your average member of the public, is sovereignty to be found in distant laws they have long lost touch with, a Parliament they regrettably take little interest in, or international treaties they are unlikely to have heard of? Or does their sovereignty stem from actual power and the pound in their pocket – from their job; their standard of living?

In my view, if we vote to leave the EU, we will be taking a massive gamble. This is not ‘Project Fear’, but the rational assessment of risk that it is incumbent on every elected representative to undertake on behalf of their constituents when confronted by such monumental choices. It is our duty to assess the danger of departure; real risks are at stake. The pound has not plummeted in a parallel fictional universe. It has wobbled in the real world because of legitimate concern that stems from our national economic Achilles Heel: our current account deficit. This is why we are vulnerable. We don’t save enough to be truly independent; we borrow too much to pretend we can ‘stand alone’.

It is being in the pocket of other nations that threatens the sovereignty of democratic peoples – just ask Greece. As Mark Carney has put it, we are reliant on the ‘kindness of strangers’. We have a huge current account deficit, and it is simply not within our power – the power of the real world, determined by hard mathematics – to act blithe to consequence.  Consider the following: Moody’s has warned that our credit rating could be downgraded in the event of Brexit. Even pro-Brexit economists accept quite openly that there will be an ‘economic shock’ if we leave. The EU does not actually set taxes, that remains a UK sovereign power, and I imagine all Conservatives would be opposed to that position changing. And yet, if there is a shock in the event of Brexit – as seems almost inevitable – and quite understandably our credit rating is hit and our cost of borrowing rises, as the key players are predicting and threatening, that could cost billions. We could vote for the ‘sovereign’ option of Brexit, and find in short time that a force over which we have zero democratic control effectively imposes a charge of billions upon the exchequer.

Some sovereignty.

Of course, it is a fact that the UK Parliament is second fiddle to the EU institutions in many areas: we should never pretend otherwise. And it is also true that, for all the strength of the northern EU member states, they are unquestionably shackled to Greece. Yet this is their problem: the Euro has been great for Germany and Holland, representing permanently favourable terms of trade with a lower valued currency than if they had Marks or Guilders, but at the price of southern pain. Compensation will have to be paid eventually, in the form of shared debt obligations and substantive Eurozone transfers to weaker states who face conversely unfavourable terms. Our renegotiation has made sure we are out of that.

And here is our opportunity; here is the positive upside to the risk of Brexit. When those inevitable treaty changes come, we need to be in there, acting for Britain, acting with Europe as a proactive, positive force. For example, we can push for completion of the single market in services, essential if we are to turn the terms of trade in our favour and start reducing our trade deficit, impossible to influence if we turn our back on the EU – and in the EU’s long-term interest if it is to achieve supra-nationally the better balanced growth that we so badly need at a national level.

I was passionately opposed to joining the Euro: had we joined we would have been a lolling corpse and no dispute, shackled to a gibbet. Yet for many years I have taken the view that to be in the EU but outside the Eurozone, with our population and clout, presents a unique platform for economic success. We have the USP that businesses can invest in the UK with unfettered access to the Single Market, trading in a major currency that is free of existential doubt (and usually stable when Brexit risk is absent). And now we have strengthened our USP further with the protections for non-Euro currencies secured in the Prime Minister’s renegotiation.

Above all, if we vote to remain, we will have put the years of indecision behind us. There is no price we could put on the value of finally making up our minds. If we Remain, Brexiteers might despair, but the message to the outside world would be incredibly positive: all constitutional doubt – from Europe to Scotland – pushed aside for a generation, our future far more secure, our long-standing USP of being a trusted, business-friendly nation once again restored.

At a time of so much uncertainty, to exchange our historic asset of business-friendly credibility for the risk of Brexit would be a betrayal of our national interest. The best empowerment we can deliver to the British people is not the illusion of sovereignty but to move our country up the international league table of GDP per head, something we cannot conceivably achieve amidst the uncertainty of Brexit. It is in our national economic interest to remain in the EU.