Supposedly, there is more joy in heaven over the one sinner that repents than over the 99 who need no repentance. Let’s hope so anyway.

I was one of the first Brits to be sent off to Brussels at the beginning of 1973, when the UK joined what was then known as the European Economic Community. I regarded myself as doubly blessed. Politically, this was a key moment, since 1973 saw the EEC’s first enlargement, with the UK, Denmark and Ireland joining the founding six member nations (France, Germany, Italy and the Benelux countries).

From my own professional point of view, as one of the early environmentalists, it was also a superb opportunity. I was appointed as the first head of the European Commission’s newly-established and quaintly named ‘Prevention of Pollution and Nuisances Division’ and given the job of pushing ahead with the EEC’s first ever Environmental Action Programme.

In 1979, six years later, I became a Conservative MEP (for Hampshire East and the Isle of Wight) in the first ever direct elections to the European Parliament and was elected Vice-Chairman of the Parliament’s Environment Committee.

I like to think that EU-wide environmental work, to which the UK made a major contribution, made a difference. Ironically, in December 2015 – as the UK’s campaign to leave the EU moved into top gear – I went to Brussels to be presented with WWF International’s Leader of the Living Planet Award for the work which I and three EU colleagues had done in drafting and pushing ahead with the EU Habitats directive which 25 years later has resulted in what is probably the largest network of protected areas on the planet, known as NATURA 2000.

In the run-up to the European Referendum in June last year, I founded and co-chaired Environmentalists for Europe.

I still believe passionately in the environmental and animal welfare objectives for which I have campaigned for most of my life. As we leave the EU, I don’t want to see us throw out the baby with the bathwater. I hope we hold firmly on to the ‘acquis’ and, as Environment Secretary Michael Gove put it in his speech to the Conservative Conference this week, I hope we seize the opportunity to move ahead in areas where EU action still lags.

This time last year, after the shock of the 23rd June vote, I – like so many other Remainers – was still busy applying salve to the wounds.

So why have I changed my mind now?

For me the critical moment came a couple of weeks ago when EU Commission President Juncker gave his State of the Union address to the European Parliament. The vision he presented of an EU with a single government, and with directly-elected EU ministers with EU-wide responsibilities, including finance and defence, was quite simply – it seemed to me – totally over the top.

Up until then, I was still ready to argue that if you wanted to steer the ship in a different direction, the best thing surely was to stay on board and try to seize control of the steering wheel. In other words, fight from within for change.

But the ship metaphor doesn’t really work. The train metaphor is a better reflection of reality. Mr Juncker’s Federal Express is heading down the track at an ever-increasing speed in a direction we really don’t want to go. Even if Britain stayed on board, I doubt if we would be able to change the points on the track ahead, or even slow the train down.

Boris, I have to say (but I would, wouldn’t I?), wrote a brilliant 4,200-word article in the Daily Telegraph pointing all this out at more or less the same time that Mr Juncker was giving that unfortunate speech. Boris argued that for 40 years Britain has been trying to nudge the EU towards a different destiny and on the whole we have not had much luck.

The time has come to bail out, he asserted. I agree. We may argue about the length of the transition or ‘implementation’ period but there cannot surely be any longer any doubt what the ‘end-state’must be.