Independence is a fringe issue in Wales. Just 12 per cent of Welsh voters support it, and that figure has been stubbornly consistent. But it is far from implausible that within a decade Wales could find itself standing alone, not through any conviction that independence is the best bet, but because the UK has marginalised Wales.
Wales is in a weak negotiating position already, as the Scottish referendum campaign has shown. Take the Barnett Formula, which adjusts the amount of money received from the Treasury by Scotland, Wales and Northern Ireland. An expert commission, led by respected economist Gerald Holtham, pointed out that if Wales were treated on the same basis as an English region it would get some £300million more a year. But the pro-unionist parties have pledged to keep the Barnett Formula in place (which provides Scotland £4bn annually) as part of their case that the UK is 'better together'. Wales, Gerald Holtham has concluded, is to be treated as "the runt of the litter… like the youngest child of a poor family that gets only hand-me-down clothes, whether appropriate or not in style or size." Such is Wales' lack of leverage that the Treasury didn't even feel the need to dispute Holtham's analysis; it simply ignored it.
Welsh political elites are beginning to feel that the union is unresponsive to its modest demands. "The United Kingdom is not a 'sharing union'. It is rather a realpolitik union. Those with the loudest voice and a credible threat of secession get to have most influence on how resources are allocated,"says Prof Richard Wyn Jones of Cardiff University's Welsh Governance Centre.
But what if Scotland were to leave the UK? Might the union become more responsive to Wales? Much will depend on how Scottish secession is conducted. It is in the interests of unionists to be magnanimous; but stark statements about currencies, defence and the economy suggest that unionists' instincts are to let the nationalists stew in their own juice. If this instinct were to govern the secession negotiations and the eventual terms of independence, it might unnerve Welsh political elites and make them fear that a similar dynamic will characterise government in the rump UK, making Wales even more powerless than it is at present.
Of course, it is possible that Whitehall will accommodate Wales in such circumstances; but it seems unlikely. England's relative size will have jumped from 85 per cent of the UK, to nearly 92 per cent of the rump state, and a resurgent England, and its future in Europe, is therefore likely to command greater attention at the centre.
If the polls are correct, Wales's wish to remain in the EU would be overwhelmed by England's wish to leave. Not only would that create a clash of values but it would also create deep unease about Wales' economic wellbeing, which would have political consequences. The little regional policy there is within the UK is driven from Brussels, not London. If the EU aid tap was turned off, with nothing equivalent in its place, the concern that economic policy is pre-occupied with London and south east England might shift political thinking on the left in Wales. A union dominated by a larger neighbour, especially one standing outside the EU, and with a powerful centre-right presence, is a very different proposition from the current union eulogised by unionist politicians in Wales.
At the time of writing, a No vote in Scotland still seems the most likely outcome; but, with the lead narrowing, Scottish secession is plausible. Such an eventuality would have profound and far-reaching consequences for Wales, especially if, at the insistence of overbearing centre-right concerns in England, the rump UK exits the EU. It's about time that the Welsh started to face up to the fact that the ground beneath is moving.
Lee Waters is Director of the Institute of Welsh Affairs.