I am writing this in Berlin while attending an international inter-parliamentary conference on freedom of religion and belief. Parliamentarians have come from all over the world and from every continent bar Australia. And the question put to me by almost everyone I meet? Brexit. I have yet to meet anyone who doesn't think the UK has been either mad or stupid.

My own position is that of the realist: the decision has been made (in a non-binding referendum that now puts a wider question over the nature of parliamentary democracy), the boat has sailed (with some enormous holes in it), and, even if we wanted to go back on the referendum result, our position is now seen as having moved in the eyes of our interlocutors in Europe and beyond. So, we now have to get on with it and shape the future, whatever this might bring.

In a session this morning Ján Figel (Special Envoy for the promotion of freedom of religion or belief outside the EU, and chair of the Christian Democratic Movement in Slovakia) remarked that there are three types of people: commentators, lamentators or doers. How pertinent. We can comment, lament or act. It is a choice.

So, what I go on to write now does not ignore the Brexit vote, but it does pay attention to some of the phenomena arising from it that need to be taken seriously because of the impact they have on our culture and the nature of our discourse. I'll put the point in the form of a question.

Is a promise still a promise even when the person doing the promising has no authority to make the promise, no responsibility for fulfilling the promise made, or bears no accountability for the consequences of the promise not being kept?

Well, we know that £350 million is not going to go into the NHS, despite what was written on the side of a bus and vigorously defended in the media by its authors. Actually, it was never going to happen. The only question is why so many people ever believed it. It was not costed, it had already been promised three times over, and none of those who promised it had any authority to do so. Yet, to question it was deemed disloyal or unimaginative.

Yesterday the Sun called the EU spiteful for suggesting that Brits might need to pay for a visa to visit countries such as Germany of France. Well, what did they think would happen? The EU isn't a benevolent society for people who have slagged them off for decades as corrupt, lazy and incompetent. Maybe we will learn what our £350 million actually bought us – like free movement and easy/cheap travel.

How would you answer those international MPs who ask what preparations were done in order to enable Brexit to happen? Given that the answer is 'none', and that no one in Whitehall or Downing Street seems able to answer simple questions about what Brexit will (or, even, might) actually look like, saying limply that “we have taken back control” sounds a bit feeble and empty of content.

So, we still hear politicians telling us that we “will” get great deals, that we can forge our way in the world with other countries simply giving us the best on offer – their best interests miraculously coinciding with ours. Not “might” or “hopefully will”, but “will”. A promise. A promise made by people who cannot deliver on it. A promise with no content. And still people seem to believe the promises.

I am beginning to wonder if we might have needed (and should have heeded) experts, after all.