Here in Brussels, we did everything to accommodate David Cameron's concerns. My collaborators and I personally spent countless days and nights negotiating an agreement that was fair toward the United Kingdom and toward the other 27 Member States. I was then very surprised to see that this settlement played no role whatsoever in the campaign in the United Kingdom. At the same time it is hardly surprising.

There is a distorted perception of what goes on in Brussels. No one reports on the Commission taking a hundred initiatives from its predecessor off the table in order to shift competencies back to member state governments.

I would describe that [friendship with Greek Prime Minister Alexis Tsipras] as a utilitarian friendship. At the time, his country was facing the prospect of leaving the euro zone and many Greeks felt abandoned by Europe. In such a situation, it seemed appropriate to me to present myself as a friend to Greece. It had to do with the country's dignity.

The problem is: When two governments or institutions in Europe hold differing opinions, it is immediately a crisis.

Much as I would have liked to respond factually and truthfully to each and every piece of misinformation spread by the Brexit campaign, it was important that I stayed out of the domestic political debate. It was David Cameron's task to win the UK referendum, not ours.

Angela Merkel did the right thing. Her decision and the extraordinary willingness of the German people to take in refugees conveyed an image of Germany that is still having positive repercussions today. Unfortunately, people in Germany are no longer seeing that.

How will the exit affect thousands of British pensioners living in Portugal or Spain who will lose their access to the welfare and health systems? Fifty-three free-trade agreements, which were negotiated by the EU on behalf of all Member States, are also hanging in the balance for the UK.