AROUND this time last week I was on my way to Holy Island or Lindisfarne, in Northumbria. After crossing the border we took a detour from Coldstream and sought the site of the battle of Flodden. It is signposted but you have to make an effort to find the battle site itself, where the cream of Scots manhood was curdled in 1513.

When England and France declared war, the Scots made a foolish foray into England hoping to attack from the rear. Despite superior numbers and a good position, the Scots found their route to the north blocked by the English under the Earl of Surrey. In a few hours most of the Scots nobility and King James IV lay dying, along with thousands of Englishmen. On the site today there is a large stone cross honouring the ''dead of both countries''. Even last week a bunch of daffodils had been placed on it, with no card, the motive unknown.

The battle site itself is on English soil, and in the coming generation Henry VIII was to punish the Scots many times for their temerity in cross-Border raids. His Army marched through the Lothians burning barns and crops as they went. South-east Scotland had once been part of the kingdom of Northumbria but it owed its religious foundation to Celtic Christianity. In the seventh century, King Oswald of Northumbria was in exile on Iona and when he returned to his throne he imported an Irish monk from the Columban church on Iona to be the first bishop of Holy Island. In these days the Celtic church and its practices dominated the northern part of England and Scotland.

Holy Island is worth a visit. You have to be sure that the tide is out when you go across the causeway, and even more important that it is out when you want to come back, but there are tables posted at either end. The monastery itself is a ruin but a museum enables you to imagine what the busy life of a medieval monastery must have been. Far from being places in which silence reigned supreme, the monastery was the staging post for travellers, scholars, and for legal and fiscal affairs. Despite being cut off from all this buzz when the tide came in, Aidan still felt the need to go off for a bit of peace to a neighbouring island.

Later that day, as I walked the St Cuthbert Way into the Border Ridge, I mused on what I had seen. I had crossed a Border between two countries which were once at war and now united in one kingdom, and had met no controls. I had crossed a causeway which was controlled by time and tide, and had to pay heed to both. Isolation is tempting, confrontation is easy, but neither holds much prospect for the future. If there is a lesson to be learned from the early medieval world it is that the tide has turned once again away from the nation-state.

The all-encompassing EU in our own era is not unlike the position of the medieval Catholic Church. It claimed sovereignty across nation-states but did not control them. The Church raised taxes and administered laws. It promoted a common language (Latin) but not a single currency. In these days people often found it quicker and more effective to go to the Church courts rather than rely on the clogged judicial process of their own nation.

Those who get so het up about constitutional issues in our time and talk of historic rights, should ask themselves at which point their history begins. Do they want the Lothians to be part of England along with with Berwickshire? If they want to reinstate the historic kingdom of Scotland, perhaps they should remember that it has existed less than a thousand years. History is necessary but it is completely irrelevant in deciding what is right and good for the future. We can take models from the past, and respect the heritage handed down to us, but why should a line drawn in the sand be our determining factor?

This is not intended to be a political point. It is intended to draw attention to the fact that arguments from history are flawed in two ways. First, because they want to preserve situations which are in the past when circumstances have changed. Second, they are bound to be arbitrary in attempting to draw a line at which that history is to be preserved. Independence for the Picts? That would be hard to achieve because the once-strong Pictish kingdom has now disappeared.

What is surely important is to go with the flow of history and not try to turn the tide for reasons which are sentimental rather than practical. That could just as easily apply to either side in the current constitutional debate. It most certainly does apply in Ireland where both sides are so hung-up on emotion and cling to lines drawn in the sands of time that they seem to forget that both the Republic and Ulster are within the framework of the European Union, which allows free movement between countries, and guarantees most of what they say they want for their own communities.

Those who sing songs about battles of yesteryear, whether they be the Boyne or Flodden, are deeply mistaken if they try to make them rallying cries for our own times. Who knows how St Aidan would have voted on devolution? He would certainly have been at odds with Brussels on the date of Easter. But he did have a good idea which I commend to those who are fed up of the ''constitutional debate'' - going off to an island and letting the tide come in.