Last Sunday we had lunch in the street, gathering neighbours together in the spirit of the Big Lunch movement. Our community association is always keen to reach out to other communities, so we invited people to chat about what our European neighbours mean to us. Whichever way the vote goes, they will still be our neighbours, and we will still be theirs. Here in Brighton, we're nearer to many of them than to many of our fellow Britons.

It was convivial and warm, with only a few pockets of high-running passion. People at ease with each other, comfortable in each other's company, sharing conversation and food – baklava, tiramisu, and similar Euro-themed desserts. How a neighbourhood should be. How Europe should be.

Yet in the local pub I was surprised at how quickly the conversation turned to citizenship. 'We're going Irish,' one regular revealed. It wasn't a surprise to hear that people of eligible ancestry are thinking about becoming citizens of another country in order to remain EU citizens. That option entered my mind as soon as the referendum was called. The surprise was that citizenship came up so readily in private, when it has been almost totally invisible in the public debate.

We are on the brink of a vote in which we stand to be deprived of our citizenship, and yet it's not an issue. Those of us who vote to leave the EU will, of course, be voting to deprive themselves of their EU citizenship. Few of the rest of us seem to care very much about being European Union citizens, as distinct from the benefits that come with a burgundy passport. Few English people feel terribly European, and fewer still care to feel bonded to the institution of the European Union.

This indifference isn't terribly surprising, given the long tradition of ambivalent rhetoric from British political leaders down the years. They have told stories about Britain coming to the rescue when Europe has got itself in a mess, or judiciously intervening in European affairs, no more than necessary, in order to secure Britain's interests. They have contrived the impression that Britain is somehow part of Europe and not part of it at the same time. They have all too rarely said 'we Europeans'.

It's too early to say that this is a tragic omission, but I fear it may prove to be. There it is: fear. People protest about scaremongering. One of the complaints against the Remain campaign is that it doesn't offer a positive vision of Europe. But I won't apologise for being frightened, and I can't detach my fear from my vision of what Europe could be. Under the circumstances, it's hard to catch more than a glimpse of that. I'm grateful to Another Europe is Possible, the left-wing pro-Remain group, simply for their choice of name. It's as near as we can get to a slogan with hope in it.

Of course we'll still be able to cross the Channel or eat baklava in the event of a vote to leave, though likely at greater cost and inconvenience. But our relationship with our fellow Europeans will change if we are no longer fellow citizens. We will no longer be part of the project that reflected so profoundly on Europe's history and set out, believing another Europe was possible, to transform its nature for the better. The post-war European movement, of which the Union is a part but not the whole, refuted the assumption that European history must forever be a game of rivalries, jealousies, power politics and conflict. It did that by working to align different national and regional interests, to make Europe a collectively beneficial enterprise instead of an endless sprawl of factions and contests.
 
If British leaders had been readier to acknowledge the European project for what it was, British voters might be readier to consider the possible effects of their choice upon the rest of Europe. A Leave vote would be like a steroid infusion for right-wing nativists and nationalists across the continent. It would not take us back to the 1930s, and certainly not the 1940s, but it would foment just the kind of rivalries, jealousies and suspicions that the European project was created to overcome. It would be a vote for exclusion and closure not just at our own borders, but throughout the societies of Europe.

Since the EU would probably seek to stop the rot, it would resist giving Britain anything that looked like a reward for leaving in Brexit negotiations. And that would set Britain as a whole against our European neighbours as a whole.

Within Britain, a Leave vote would confirm nativism as the driving force of British politics. All my life I've been aware that a significant fraction of my fellow Britons would regard me as foreign because of my name, or at least as less British than they are. But for most of my adult life I've felt able to not worry about them. I don't feel I can ignore them now. It may be about to become a lot harder to explain that belonging is not a zero sum: that being more European doesn't mean being any less British than everybody else.
 
It saddens me, the way that it's the Leave campaign that appeals to people's hearts, while the Remain campaign concentrates on cost-benefit analysis and risk assessment. Yet you can vote Remain with your heart, whether you feel European or not, if only you can recognise the European ideal as something that can be symbolised by a neighbourhood street party: not some grand pseudo-imperial vision, but an ideal of modest everyday life, in which neighbours live convivially and at ease with each other. Notwithstanding the tensions of free movement and the contortions of the Eurozone crisis, this is Europe's achievement. It's the kind of thing you don't miss until it's gone.