To say Ireland and the UK are close friends and neighbours is more than just a platitude. For many generations, Britain was the first place where our people sought work when our economy faltered. And Britain was enriched by the arrival of Irish people too. These women and men provided a much-needed labour force that helped build the infrastructure in British cities and provided the teachers and nurses who taught and cared for communities. The legacy of that was a deeply integrated Irish community, which has contributed greatly to the development of this country.

Our economies are closely intertwined across so many sectors. There are now more than 60,000 Irish-born directors on the boards of UK companies. We have a trading relationship worth over £55bn a year, sustaining more than 400,000 jobs across both islands. The flow of people across the Irish Sea every day has made the Dublin-London air corridor the second busiest in the world.

Our relationship is deeper, richer and more enduring than the issue of Brexit – just as it was always more layered and complex than it appeared to be during the Troubles in Northern Ireland. However, we cannot be complacent. As in all good friendships, there must be honesty and trust. While we often – usually, in fact – agree, we should be able to disagree too. In fact I’d go further: the capacity to disagree, openly and honestly, and then to move on is the mark of genuine friendship.

We disagreed on Brexit. We hoped the UK electorate wouldn’t vote for it. But it did, by a narrow margin. And now we are determined to ensure that, no matter what else, Ireland-UK relations do not suffer as a consequence. This involves protecting perhaps the greatest UK-Ireland achievement of recent times: the Good Friday agreement of 1998. The agreement removed barriers and borders – both physically, on the island of Ireland; and emotionally, between communities in Ireland and between our two islands.

The genius of the agreement is that it provides a framework for all of the relationships on our two islands – between communities in Northern Ireland, between north and south on the island of Ireland, and across the Irish Sea. I am always struck by just how carefully woven together these relationships are, with each of the three interlocking relationships reinforcing the others. Strengthen one, and you strengthen all; damage one and you damage all.

In looking to deepen our UK-Ireland cooperation in a European Union without Britain, we are fortunate that there are already a number of East-West institutions provided for in the Good Friday agreement that could be utilised to fuller effect. We also have the British-Irish parliamentary assembly, and regular meetings of all our permanent secretaries and secretaries general.

These structures matter as much because of the personal interactions they help facilitate as any kind of formal agendas. As the UK leaves the EU, we don’t want to lose the kind of cooperation that can be fostered by a simple conversation on a corridor or a cup of coffee on the margins of a meeting. British and Irish politicians and officials need to keep working and meeting together to ensure that the understanding we have of each other does not diminish.

It is probably fair to say that our journeys as EU member states have been quite different. As an Irish citizen born just one month after our EU accession referendum, I grew up in an Ireland demonstrably benefiting from EU membership. Our membership of the EU has quite simply been transformative. It has allowed us to develop and grow into a confident country, at ease with ourselves and our neighbours.

But make no mistake either – Ireland needs and wants our neighbours to be prosperous too. We think the closest possible future UK relationship with the world’s most successful single market – a market British genius helped design – is the best way to ensure that this comes to pass.