Even if political obstacles to Irish unification were at some time in the future to dissolve, the persistence of the present scale of financial dependence of Northern Ireland's debilitated economy upon transfers from Britain would be likely to deter a majority of its people, whatever their political background, from abandoning the British connection.
That is, of course, unless the people of the Republic were to agree to take over that burden.
And it seems to me certain that the Republic's taxpayers would be unwilling to vote to accept responsibility for what would for them be a massive burden; one 15 times greater per head than that currently borne by the far larger number of taxpayers of Britain.
In the past these financial transfers from Britain to Northern Ireland were quite small: indeed all that was involved initially was Northern Ireland failing to contribute its full share of the cost of the UK's central government, monarchy and defence.
This was because when Northern Ireland secured its own administration in 1920, its economy was then in quite good shape; although it subsequently suffered like the rest of the UK from the recession that followed the wartime boom.
Then, and for many decades thereafter, it was by far the more prosperous part of this island, although there was from the start a fundamental weakness in the Northern economy. Its industrial base comprised a number of declining industries, which have since effectively disappeared: shipbuilding and associated engineering trades, as well as textiles and clothing.
The first estimates of the regional output of Northern Ireland were made by Prof Charles Carter in respect of the year 1953. These enabled me in 1956 to make the first detailed economic comparisons between the Republic and Northern Ireland, which showed that output per head in Northern Ireland was 27 per cent higher than in our State and that, due to financial transfers from Britain (for example, through the social welfare system), living standards there were then 33 per cent higher than here.
When 16 years later I next came to write in Towards a New Ireland about these two economies as they stood in 1969, that North-South gap had been only slightly narrowed. In that book I noted that during much of the 1960s the economies of both parts of Ireland had been growing at about 4 per cent a year, ie 70 per cent faster than the very sluggish British economy.
And I went on to suggest that if, as then seemed possible, eventual EU membership enabled Ireland to accelerate this growth rate to perhaps 5 per cent a year, both parts of the island might by the late 1990s have caught up with Britain in economic terms. The North would then no longer require financial transfers from Britain, which would eliminate the economic barrier to Irish political unity - whatever about the political barrier.
Well, I was half right. During the subsequent three decades the Republic's average growth rate was in fact close to what I had projected. As a result, by the end of the latter decade Irish output per head had come within 3 per cent of the British figure. But economic growth in Northern Ireland during these three decades had not performed as I had hoped. In fact the growth rate it had been achieving during much of the 1960s actually halved, to 2 per cent a year.
As a result the area became hugely financially dependent on Britain. I am not aware of any study that attempts to explain this development. But it is difficult to believe that the IRA campaign of violence had nothing to do with it. Headlines of murder and arson in the world's press certainly greatly discouraged investment in the North, both foreign and domestic.
Indeed, during these decades, native enterprise, which had previously seemed to thrive there while being seen as deficient in the Republic, seemed to fade away. Much of manpower and human energy of the area had to be channelled into what became a grossly swollen security industry.
And as the public sector grew, the private sector languished.
The more the IRA sought to wreck the infrastructure of Northern Ireland, the more the region lost any chance of being able in the future to gain freedom from the financial dependence that bound it ever more tightly to Britain. Of course, we cannot know how rapidly the Northern economy might have grown under conditions of peace and stability.
Perhaps I had been optimistic in thinking that in such circumstances it could have kept up with the Republic and actually caught up with Britain. But what is quite certain is that the IRA campaign pushed Northern Ireland further into the British embrace. For any thinking nationalist this was clear lunacy.
This unhappy situation was not helped by unionist determination to reject non-political links with the Republic that might in time have helped to restore the North's economy.
If I had been David Trimble at the Belfast negotiations in 1998 I would have refused to sign unless the British agreed to ask the EU to permit Northern Ireland to apply a corporate tax rate nearer to the low Irish than to the high British level - a request that it would have been politically very difficult for other EU governments to refuse. Another condition would have been that the Irish Government agree to permit Northern Ireland to share fully in and benefit from the highly skilled efforts of the Industrial Development Authority, which is probably the world's most effective industrial promotion body.
Instead, Trimble's narrowly political view seems to have led him to seek to avoid any economic differentiation from Britain, however valuable that might have been for Northern Ireland, and to choose less economically valuable sectors for the North-South co-operation process.
The concept of seeking a share of the Republic's new prosperity, in ways that need have had no political implications, seems to have been deliberately shunned.
As a result, Northern Ireland now has a very weak economy, which in some important respects is akin to the East German basket case; above all in the debilitating scale of its economic and financial dependence on the larger neighbour to which it is politically linked.
In 1953 the North, with 31 per cent of the island's population, was responsible for 38 per cent of its output. Today, with only a slightly smaller share of population, it accounts for barely 23 per cent of what this island produces. Surely it is more than time for its politicians to turn their attention to reversing the relative decline of their part of this island.