Iain Duncan Smith is a former Secretary of State for Work and Pensions, founded the Centre for Social Justice, and is MP for Chingford and Woodford Green.

After the argument and division of the referendum, the Supreme Court case and long-winded debates in Parliament, tomorrow, when Theresa May sends Donald Tusk the letter triggering Article 50, the clock on our remaining two years in the EU will start counting down.

Ironically, this letter follows the muted ‘celebrations’ on Saturday, when 27 EU leaders met to mark the 60 years ago of European integration. For it was in Rome that the first European treaty came into force, signed by the six founding members. As I watched the pictures of this gathering, without our Prime Minister, I thought back over the last 44 years of our membership and to what degree my own opinions had changed over the years on this issue.

I was 21 and at Sandhurst, completing my officer training for the Scots Guards, when the Common Market first caught my attention. Even though I had two parents and two sisters living and working in Rome, the subject of our membership of the EEC never really came up. Although I didn’t get much involved with the referendum, like many of my colleagues I was aware of the arguments about sovereignty but paid them little heed, believing what we were told – that this was simply about being a member of a ‘Common’ market place and I felt we should stay in.

Then, 25 years ago, I was elected to Parliament to serve the people of Chingford (later Chingford and Woodford Green). Since being a candidate in the 1987 election in Bradford West, I had watched the toppling of Margaret Thatcher with horror, particularly after it was brought on by the strong disagreements in the Parliamentary Party over the European issue and the proposed new treaty of Maastricht (officially, The Treaty of European Union). Later, uneasy with what I read about the treaty and just before John Major signed, some of us parliamentary candidates cheekily signed a letter to The Times, urging him not to sign it. However, once elected in 1992 – with the ratification of the treaty being rushed at us – I made a point of studying the treaty in greater detail. I particularly focused on the role of the ECJ, learning how it had become the ratchet and engine of ‘ever closer union’ through its interpretations of the treaties.

My opposition, coming some weeks after my arrival, wasn’t easy but I became convinced that the treaty would be a step too far and would create the momentum within the newly named European Union to carefully but methodically eradicate the power of the nation state. This seemed a far cry from what we had been told at the time of the referendum by our leaders. Even at this stage, I didn’t want to leave but hoped we could turn it around.

This was no accident, as reading back I began to realise what had been going on. For the Single European Act and the Maastricht treaty was in effect the same treaty, divided into two parts. When seen together they represent the largest shift of power to the EU institutions including the Commission. It was hidden under the veneer of the market place, but in fact this was an enormously powerful political power grab. The designer of this process was Altiero Spinell, the little known (in the UK) one-time Italian Communist and arch-believer in the creation of a supranational state called the European Union.

At the heart of his project was the belief that the problem in Europe was competing nation states. Such competition, he believed, resulted in war. This chimed with a number of those engaged in this European project and lay at the heart of the two treaties. I don’t blame him and others for taking that view, having lived under Mussolini and other dictators, but I have always believed he was wrong to blame nation states. Competing nation states, as evidenced by much of the English-speaking world during and after the Great Depression, didn’t turn to extremism. The problem in Europe was the absence of robust democracy underpinned by strong democratic institutions. Democratic nation states governed by the rule of law, in which the citizen has inalienable rights, withstood the worst the depression could throw at them.

After years of trying, Spinelli’s supranational project provided the impetus for the negotiations which led to the Single European Act of 1986 and the Maastricht Treaty of 1992. French President François Mitterrand reversed Charles De Gaulle’s previous hostility to anything but an intergovernmental approach to Europe after meeting Spinelli, and even spoke in favour of Spinelli’s approach in the European Parliament. Mitterrand’s decision to reverse French policy ensured the support of a majority of national governments to trigger the treaty revision procedure.

I came to believe that, no matter what had been said before about the European project, this was the critical moment when the EU’s destination became clear. It was not about a market place, for that was only a device to create this wider and far deeper concept. I said at the time that if the UK ratified the treaty, then more would follow and in time it would become impossible for the UK to remain in this growing supranational state. What followed was a series of treaty revisions including a de facto constitution, governed by the overarching supremacy of European law.

From this flowed so much, including our exit from the ERM and avoidance of the Single Currency. I recall how often we were warned that we couldn’t afford leave the ERM, yet when we did the economy boomed. Similarly, when I became leader I determined to change William Hague’s policy on the Euro and say simply that we would never join. Again, we were told it would be a big mistake and that the Euro was bound to be a success. Now imagine what would have happened at the time of the crash had we been in the Euro; for that, you need only look at France, Italy and Spain, with their high unemployment and financial crisis.

Throughout, in the UK this reality has hardly dared raise its name, with successive Prime Ministers fighting fruitless ‘rearguard actions’ in negotiations and then claiming at home that we were winning in Europe. Remember Douglas Hurd saying that Maastricht marked the high water of European federalism and John Major saying it was ‘game set and match’ to the UK after Maastricht. These words sound hollow now and found echoes twenty-four years later in David Cameron’s claim to have negotiated a special deal for the UK. They were wrong then and he was wrong last year. What both showed was that the European Project brooks no real exceptionalism, and its destination – a United States of Europe – is believed and understood throughout the EU.

It was this refusal to admit what the project was all about which led to Vote Leave winning the referendum. In a recent Centre for Social Justice/Legatum review of the vote, it found that those who voted to leave cited regaining sovereignty as their number one reason for voting, more than migration and money.

Twenty-five years ago, with the passing of the Maastricht treaty, the EU decided to leave the UK. We are now bound on a course to formalise that decision. We do so with political leaders in the EU beginning to use common sense terms as they now speak of needing good arrangements with the UK to protect their markets and their access to financial services. Whilst there is much to be done and plenty of hard work ahead, I am confident that Theresa May and her team can deliver an arrangement that suits both the UK and the members of the EU. After all it must be in everyone’s interest, as President Juncker said the other day, for the UK and the EU to part as friends, co-operating and trading.

Imagine that: a Prime Minister of the UK no longer forced to describe their activities as ‘winning in Europe’ but, instead, able to show that we are instead winning outside of the EU.