When I told a senior government official that I had put £20 on Brexit as an insurance policy – we believers in Europe will need something to cheer us up if the vote goes that way – his reply was: “Only twenty quid?”

This reaction epitomises the extremely gloomy mood among most of my pro-European friends and acquaintances. And while they dismiss Alexander “Boris” Johnson’s antics as beneath contempt, many people are surprised at the way my old friend Lord Lawson is putting himself around as someone who boasts about living in France but is blithely relaxed about the prospect of Brexit, indeed actively propagating it.

Lawson’s position is also interesting because he is a grandfather. The opinion polls have to be treated with a kilogram of salt after last year’s general election; however, even allowing for polling error, what seems incontrovertible is the finding that the young tend to be strongly in favour of our remaining in the European Union, whereas the so-called “grey vote” is predominantly in favour of Brexit.

With due respect to the grandfather generation, they do not, according to the polls, seem to be paying much attention to the views and ambitions of the younger people who will have to cope with the consequences of Brexit rather longer than they will.

Moreover, one of the paradoxes of the position in which David Cameron has landed us is that he has managed to shoot himself in the foot by altering the system by which the young come on to the register. Thus, instead of being automatically eligible to vote on reaching the age of 18, they have to go through a conscious act of registering.

This may have suited Cameron when he was panicking about losing the last election – and let us not forget that it was concern about the electoral threat from Ukip that induced him to commit to a referendum in the first place. Unfortunately it does not suit him now. It is a safe bet that, as a result of that earlier cheap electoral trick, many of the youngsters on whom Cameron and Osborne should be relying on for the referendum will find that, unlike their grandparents, they have not got around to being eligible to vote on the biggest political issue of their young lives.

Of course, another paradox in this bizarre affair – an affair that has now become big news around the world – is that the prime minister cannot possibly win this referendum without the support of the Labour party. As I have gone about my travels in recent weeks, a constant refrain has been: where is Labour? Yes, the stakes are so large that her majesty’s opposition, and commentators such as myself, have – to coin a phrase – no alternative but to support Cameron and Osborne on this issue, even if we regard their economic policies as misguided and their social policies as harmful and destructive.

Well, the Labour party turned out on parade last Thursday, and Jeremy Corbyn pronounced that there was an “overwhelming” case for our remaining in the EU. This is statesmanlike behaviour and judgment. Whatever the deficiencies of the EU, we are not going to remedy them if we leave. And the Lawson/Johnson idea that we can renegotiate our way into the advantages of belonging to an organisation that we have just left is for the birds. Messy divorces do not work like that.

From my own recent soundings in Europe, I can conclude with reasonable confidence that every one of the other 27 states of the EU desperately wants us to “Remain”. But I also conclude that, if we do indulge in Brexit, the attitude of the others, their patience having been sorely tried, will be seriously uncooperative.

The process of renegotiating trade arrangements, and from a position of the weakness of the suppliant, could take decades, just as it took successive Conservative and Labour governments decades to be admitted to what is now the EU in the first place.

All this stuff about “no problem in negotiating new arrangements” is redolent of the 1950s, when, having failed to sign the Treaty of Rome in the first place, we tried to join the others in a broad European Free Trade Association. That came to nothing and, as our negotiator at the time, Reginald Maudling, commented in his memoirs: “The French argument basically was that the British wanted to take everything and give nothing, that we were not communautaire.” In the end we set up, with other non-Common Market members, a rival that proved inadequate and led to our eventual applications to join the real thing.

There are lots of things wrong with the real thing. But we really do have the best of both worlds by remaining in the union while being outside the eurozone and the Schengen passport-free area. Above all, Europe and the rest of the advanced economies are faced with so many problems that what is needed now is maximum cooperation, not splendid isolation.

Oh, and by the way: much of the regulation so many people complain about was necessary to make the single market work. Britain, under Margaret Thatcher and her hard-working negotiator Arthur Cockfield, was the main force behind the formation of the single market. And those latter-day Thatcherites who evoke the lady’s name in favour of Brexit should heed the words of her biographer Charles Moore: “Mrs Thatcher was the most effective promoter of European integration Britain has ever known.”