MY summer holiday this year began with one last work commitment – I had accepted an invitation to speak at the Féile an Phobail – the West Belfast Festival – about independence, Brexit, and the connections between the Irish and Scottish situations in this unprecedented context. It’s pretty unarguable that both countries’ interests are being trampled on by the UK Government’s reckless approach.

After Belfast my plan was to head to Galway for a few days to relax and stop thinking about the chaotic political mess we’re having to endure. But as my train sped from Belfast to Dublin I couldn’t help but carry on thinking about what Brexit is doing to the island of Ireland, and about what the implications might be for Scotland too.

The ongoing dysfunction of the Stormont assembly is a problem with many complex aspects, from allegations of corruption to long-standing tribalism, and it has come to involve such a long list of issues from the Irish language to equal marriage that there are no quick or easy solutions.

READ MORE: What the Brexit deal on the Irish border means for Scotland

But while it’s not a simple direct result of the Brexit vote, that situation does raise such existential questions for Northern Ireland that political paralysis surely isn’t a surprise.

It was essential to the achievement of peace, and the creation of a democratic assembly to run Northern Irish affairs, that fundamentally different ideas could be allowed to coexist. Neither side winning, but neither side losing.

A necessary and useful ambiguity. Within the context of the EU with its single market and customs union, the border didn’t prevent that solution from working.

It could remain so open that it might barely even exist in practical terms, while still sitting there on the map reassuring the Unionist community that, in their terms, Ulster was still British.

The point is that a border means different things to different people. To some it’s more than just a line on a map, it embodies their very identity and defines the place in which they invest feelings of patriotism. To others it’s a largely administrative line, no more personally meaningful than the line between council areas.

A border carries meanings of culture, economics, family and society, but it isn’t a barrier – at least not while it works properly.

A border between friends is a place to cross, to meet, to trade; it’s something which brings people together instead of keeping them apart. Walls and fences are signs that a border isn’t working.

Staying ambiguous about the meaning of the border across the island of Ireland, which was possible because both countries were part of a wider political and economic union, allowed it to have as much or as little significance as people wanted to invest in it, and the fundamentally different ideas about it could coexist.

Turning it into an EU/non-EU border threatens that, and so it was surely inevitable that the democratic structures built in that context would be thrown into confusion, whether the trigger issue was renewable heating, equal marriage, or anything else.

The utter failure of the UK Government or the Brexit cheerleaders either to respect the majority Remain vote in Northern Ireland or to settle on practical solutions to keep the border open, flexible and helpfully ambiguous is one of the most irresponsible aspects of the whole mess David Cameron’s referendum unleashed. But however it plays out over the coming months, it also raises questions for Scotland.

Inside both the UK and the EU, the border across the British mainland between Scotland and England is equally ambiguous. For those with a strong sense of national identity, it can continue to be a defining issue. For others, it can be more or less invisible. It allows each jurisdiction to acknowledge the range of their authority, but it places no barriers in the way of people’s lives. It is as porous as a border should be – a place to cross freely, not a place to stop or be stopped.

READ MORE: Brussels strikes fresh blow to UK's Irish border proposals

Of course our context is very different to that in Northern Ireland. We have none of the terrible history that resulted from the partition of Ireland, and throughout the long development of the campaign for Scottish independence there has never been any serious suggestion that a “build the wall” attitude exists. But inevitably, if the reckless extremists in the UK Government succeed in removing the whole UK from its wider political and economic union, the EU, then the case for independence will need to evolve in new ways.

In these times of hostile “take back control” ideology, the idea of borders as barriers needs to be challenged. If independence is to be seen, in England and in Scotland, as an idea that can make people’s lives better, we must reach out to make the case for open, free and flexible borders.