The glaring anomaly that the political class has spent years ignoring has suddenly locked itself firmly to the radar. And if, next Thursday, the Scots vote no to secession (as the good money says they will), it will become a fixed part of our national discourse.
Events of the last few days have cracked open the bottle, and the genie of devolution for England is well and truly out of it. The eleventh-hour bribe to the Scots of yet more powers for Holyrood is already having ramifications far beyond its purpose. It has made inevitable a full-on debate that until now has been the preserve of constitutional anoraks and fringe grouplets.
The West Lothian question is about to become mainstream.
Assuming the Scots reject independence, the case will, in the context of the plan for extended devolution drafted by Gordon Brown and championed by the three main pro-union parties, be unanswerable.
Because if, as the English see it, it is right for other nations of the United Kingdom to have their own national parliaments and assemblies, to have the power to decide on all manner of affairs from health and education, to housing, local government and economic development, as well as exerting, so it now seems, future control of income tax, why not us?
If it happens, 'devo-turbo', or whatever it's now called, will create within our political system an imbalance of the kind that no true democrat can ignore. Permitting Scottish MPs at Westminster to continue casting votes on laws affecting every sphere of English life but which increasingly will not, thanks to ever-deepening devolution, impact in the slightest way on their own constituents north of the border, will stretch the democratic elastic to breaking point.
So the debate will begin; it won't be wished away. And how those of us on the Left intervene in that debate, if at all, is a key tactical consideration. Opposing any sort of devolution for England would be a non-starter. The inherent injustices of the status quo will be so blazingly apparent that those who argue for its continuation will quickly find themselves marginalised. People know a stitch-up when they see one, and trite injunctions about putting class before nation will have little resonance - particularly when large swathes of the Left have been happy enough to throw their weight behind the 'Yes' campaign in Scotland.
Fearing accusations of being peddlers of nationalism, though, some progressives might balk at the idea of supporting full-scale national devolution for England and opt instead for the alternative of handing power to the English regions. But that argument has already been lost. Regionalisation is a dead duck. Poll after poll has demonstrated that the English have little enthusiasm for it. They may feel affinity with their home cities or historical counties, but they hold no affection for the artificial, and relatively modern, territorial units that constitute the regions. Proud Geordies do not consider themselves proud 'north-easterners', as the 2004 referendum in that region - in which 78% rejected the proposal for a regional assembly - showed. Moreover, at a time when national consciousness is growing elsewhere in these islands, leading to greater autonomy and cultural reawakening, the English are hardly likely to accept a deal on devolution that doesn't recognise their own nation as a legitimate political and cultural entity.
Other suggested remedies - such as the McKay commission's proposal for some kind of gentlemen's agreement at Westminster to allow MPs representing English constituencies to have the final say on legislation affecting only England - are inadequate and impractical.
So the most desirable and straightforward option must be for the establishment of a separate and distinct English parliament, to take its place in a federal structure alongside Holyrood, the Senedd and Stormont. And it's a proposition the Left should support. In championing it, we can frame the argument as one that speaks to the best of our values: for democracy, self-determination and deeper enfranchisement; for an inclusive, civic nationalism of the kind advanced by progressive forces from William Blake to Billy Bragg and enshrined in Tony Benn's eminent Commonwealth of Britain Bill and the writings of George Orwell. Look to the example of the National Collective in Scotland to see how well it can be done.
Or we can decide that we want nothing to do with any movement giving oxygen to anything resembling an English national identity and abandon the battlefield entirely. Do that, however, and watch helplessly as the campaign for English devolution is usurped by the likes of Ukip - or worse - who will infuse it with just the sort of jingoistic streak it doesn't need and present themselves as the patriotic champions of democracy fighting the politically-correct, anti-English ranks of the Left. Think for a moment how that clash will play out among a disgruntled English working-class seeking political expression for their concerns over the effects of multiculturalism and mass immigration in their communities.
Claims that an English parliament would be dominated by the Conservatives are exaggerated. The same was said about Labour's likely influence over the devolved administrations in Scotland and Wales. Those fears proved unfounded. Not forgetting, too, that at several general elections Labour won more votes in England than any other party.
Support among the English for their own parliament is increasing all the time. A recent poll from the Left-leaning Institute for Public Policy Research had it standing at 54%. Ten years ago, it stood at 24%.
So the Left should be out of the blocks quickly when the debate over devolution for England begins in earnest after the probable no vote next Thursday. And we should shape the campaign for a new settlement in our own image - an image that draws on every democratic and radical movement England has produced from the Levellers and Diggers to the Chartists, from the early Christian socialists to the Jarrow marchers, from Tolpuddle to the Suffragettes, from Wat Tyler to the pioneers of the New Unionism.
That's a history any progressive should be proud to shout about.