I can pinpoint the exact moment when it became clear to me that the European Union was incapable of changing and that ultimately Britain's days in the EU were numbered.

It was on Thursday, 10th July, 2003 at the signing ceremony to close the European Constitutional Convention. I had spent almost 15 months working full-time in Brussels to negotiate the document that eventually became the Lisbon Treaty. Officially I represented Parliament, but as one of the 13 which formed what was known as the 'Presidium', I had close contact with all Whitehall Departments as well as Number 10.

Everyone was standing around sipping champagne to the strains of Beethoven's Ninth. But I was in no mood for self-congratulation. I grumpily scribbled my name, declined the drink and headed straight for the airport.

Seeing Europe's power politics operating up close had not been pretty. It was in the worst traditions of the EU – a mule-like refusal to listen to democratic concerns or accept any suggestions of deviation from the orthodoxy of political integration.

Giscard d'Estaing did a masterly job of managing the whole event on behalf of the people who, in his opinion, mattered. Apparent progress turned into illusion. Until the last 48 hours, we thought we had agreement on a whole range of issues – and it all unravelled.

I shouldn't have been surprised. The EU is an institution that keeps heading on a single trajectory, incapable of critically examining the direction it is proceeding. Questions like democratic accountability and economic competitiveness, which are so central for us in Britain, are downgraded in case they become a diversion from the European Project. I call it integration at whatever the cost or consequences.

This referendum is our opportunity to set ourselves free from an organisation that only serves its own interests. That is why I am proud to chair the Vote Leave campaign.

Outside the EU we can return real democratic control to important areas of national life; from international trade, the right to work and live in Britain to business regulation. These things affect our daily lives, but we hardly ever have anything resembling meaningful debates on some of these things as our parliament has so little power.

We would also regain control over the £350m subscription we pay Brussels every week. We could spend it on schools, the NHS, the environment, cutting the deficit – the choice will be ours.

Voting Remain on 23 June is not just about staying in the EU as it is today, but it is staying in the EU as it will look in 2025 or 2035. It has a clearly mapped out path. The ambition is set out in the so-called 'Five Presidents' report published last summer. It details a three-stage plan to be completed by 2025 for "a political union including ideas such as a Euro-area treasury and unified external EU representation".

There is no explanation in there about how remorseless centralisation will actually create the "better and fairer life for all citizens" the report wants. The literal meaning of Utopia, let us remember, is "no place", a fantasy land.

The Five Presidents' Report – its title alone is a reminder that we are not dealing with a very streamlined institution – describes an EU where the priorities of the Eurozone will gradually take over Brussels institutions. There is little discussion of how they can serve the interests of countries with their own currencies, just a lofty assurance that they will be able to join the Euro in future. In other words, the faithful are kindly keeping their church doors open to new believers, dissent may be tolerated, but not encouraged.

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Let us be charitable and suppose the EU sticks to the commitment it gave David Cameron in the renegotiation that the Eurozone will respect the rights of non-members not to be discriminated against, even as it swallows up the Brussels institutions.

If we stay in, David Cameron's non-reform package will have exhausted our negotiating capital. The next time a prime minister tries to bang the table for Britain, it will be all too easy to remind him – "what are you talking about? Your people support the EU".

We may be able to fend off some negative change, but our ability to bring positive reform will wither. At the same time we will remain subject to all the restrictions on our sovereignty and economy that Brussels brings.

So in a few years' time, as the bank UBS said recently, there could well be another referendum dilemma confronting Britain – leave the EU or join the Euro. Then the warnings of doom will be similar to those we hear from the Remain people today – and to what the supporters of the Euro and the Exchange Rate Mechanism (ERM) mistakenly claimed years ago.

One of the most depressing aspects of the European debate is how the same discredited warnings keep popping up.

In the run-up to joining the ERM, the head of the Stock Exchange said London's status as Europe's financial centre would be threatened if we stayed out. The governor of the Bank of England warned that only ERM membership could provide a credible monetary policy. The CBI was an enthusiast.

We went in, we crashed out – and enjoyed our longest period of growth for three centuries.

It was not long, though, before they were at it again, this time over the single currency. We had warnings of disaster from the CBI and multinationals who thrive in the corporatist Brussels set-up.

Michael Heseltine said staying out of the Euro was "threatening great swathes of British industry".

Thankfully, the Labour government did not listen. And free of the shackles of a fixed exchange rate, we have recovered from the financial crisis more quickly than even the stronger continental economies, let alone those plunged into penury by the Euro.

For years, British governments have tried to be pragmatic about Europe. They have taken the view that you can always kick the big decisions down the road. Well, now the time has come to decide.

If the EU were an energy supplier or a bank, you would long ago have stopped believing its marketing, you would have seen it was hopeless value for money and never listened to its customers. You would just move your account.

It is time for Britain to recognise that Brussels has had enough chances. And that the only safe option is to Vote Leave.

Gisela Stuart is Member of Parliament for Birmingham Edgbaston