The English question has suddenly shifted from being one of the enduring Cinderella issues of British politics to becoming the focal point for an increasingly heated - if not panic-stricken - set of political debates.

But while the Westminster parties scramble to relocate some of the age-old answers it has elicited, the posing of this question now takes place against an entirely novel backdrop. The terrified realisation that the referendum's outcome is on knife-edge, together with the speedy cobbling together of a substantial offer of further devolution for Scotland, have brought questions about the governance and representation of England tumbling out of the constitutional closet. And so, for the first time in over a century, this major issue, and a host of other related questions about the structures and balance of the Union, are at the heart of a much wider and deeper democratic debate than the political parties ever imagined would happen this side of the border.

In this situation, the unionist parties and their leaders are going to have to show qualities – of leadership, vision and constitutional imagination – which have, for the most part, been missing in debates about policy in this area. It is now time for both Tories and Labour to accept that putting the UK on a more sustainable, democratic and federal footing requires them to set their own partisan self-interests to one side, and to begin designing a bottom-up conversation about constitutional change. But, at the same time, it is also imperative that they revisit some of the main competing options which represent different possible answers to the English question.

Perhaps the most appealing solution to the conundrum of finding a way of protecting and representing English interests in a reformed UK is an English parliament. But this idea – which has long had a small and zealous set of advocates – remains the most difficult to contemplate, given the size of the English population in this most unbalanced of unions. Some of its proponents are, in effect, nationalists who want to see the dissolution of the UK, from the ashes of which they see an English nation reborn. Others want to revive the old but never achieved idea of 'home rule all 'round' within the UK.

Rather strikingly, there are voices now emerging on the right of the Conservative party, and indeed in Ukip, who want to create a de facto English parliament in the House of Commons by restricting votes on English legislation to English MPs. On certain sitting days, the Commons would become a parliament for England. This is the model outlined recently by John Redwood MP and supported by ConservativeHome. Some have even floated the idea of an English executive authority to protect English national interests – in the form, for instance, of a new first minister for England. Yet the prospect of an executive authority that is split between English and UK jurisdictions has the potential to generate confusion and dysfunction at the heart of government.

As yet, this idea does not command overwhelming support among the English: the most recent results of the Future of England survey, for instance, indicate that this is the preference of 18 per cent of English, when it is offered as an option alongside other possible reforms (though 54 per cent indicated their support for it when it is presented as a stand-alone option). And this may well reflect an appreciation that an English parliament would be more powerful than the House of Commons itself. A fully federal solution to the reform of the union therefore falls at the hurdle of the fundamental asymmetry of power in the UK. This would have been far less of a problem in the 19th century, when the British empire spanned the globe and the domestic reach of the state was limited, but it is an intensely difficult one now.

This idea also – importantly – leaves untouched the significant differences of power, culture and identity that prevail within England, and which are endemic to expressions of English national identity. And in a context where increasing numbers of the majority nation feel alienated from London – a hyper-diverse, global city, where the circuits of political and economic power are ever more detached from the country it governs – the danger is that an English parliament would give political expression to the nation-territory of England, but do nothing to address the concentration of power at the centre of government. All of this said, this idea can certainly be expected to loom large in any future discussion of the union, and has attracted some eminent new advocates.

A more diluted version of 'English votes for English laws' (EVoEL) has been the stated policy of the Conservative party at points in its recent history, with important interventions from both Sir Malcolm Rifkind (who has made the case for an English Grand Committee) and Ken Clarke, within the Democracy Taskforce appointed by David Cameron, which reported on this issue. In these slightly different but overlapping proposals, a restriction would be placed upon the ability of MPs from across the UK to support measures that a majority of English MPs do not approve of. This proposal – considered and rejected by Gladstone and a number of his successors – has long been criticised for creating 'two classes' of MP at Westminster – although Clarke's proposal steers around this problem by ensuring that all MPs can vote on the third reading of a bill. But there is also the considerable technical challenge of dividing bills by territorial jurisdiction – a serious question, given the number that carry financial implications for all parts of the UK.

Yet, these challenges are certainly not insuperable. There are already two classes of MP, it might well be argued, and this axiom may well now be trumped by the conviction of many citizens that there are two classes of constituent in the UK. And so, while there are actually very few pieces of legislation to which an EVoEL process would apply, this kind of proposal has an increasingly symbolic resonance, speaking to the growing sense of concernamong English publics – tracked by the Future of England surveys of the last three years – that the post-devolved union does not protect the interests of the largest national community in the UK. This idea has the strongest resonance with English people (40 per cent indicated support for it in the most recent Future of England survey), primarily because it appeals to a deeply felt (but hitherto ignored) sense of national-democratic justice on the part of the largest nation in the UK. While the Conservative party may well shift behind this idea immediately after the referendum, Labour has refused to consider this issue as a matter of democratic principle, believing that EVoEL is a device intended to secure Tory hegemony over England.

For this reason, it may well be that Labour – which has proved remarkably obdurate in its refusal to engage with these issues since it introduced devolution to Scotland and Wales – chooses instead to align with the more diluted proposals set out in the independent McKay Commission which reported in 2013 – with which the party has so far refused to engage. This body proposed a more diluted model of EVoEL, which would ensure that legislation was considered by English MPs at committee stage. This is an important potential innovation, but one that would not necessarily guarantee that the will of English MPs was not overridden by a UK government. Given Labour's fears and uncertainties in this area, some version of the McKay proposals might provide an appropriate starting point for the post-referendum debate among the parties at Westminster.

But for Labour there is a real danger that in opting for the apparent safety of the least radical option in this area, it is outflanked by its political opponents and framed – as in Scotland – as the party most identified with the decaying settlement of yesteryear. There are real democratic energies and forces in play in England, as elsewhere in the UK, and these will quickly turn against any semblance of the kind of Westminster fudge that has too often typified British approaches to constitutional reform. And so while Labour has recently shifted towards embracing the principle of a significant further phase of decentralisation within England – with its proposals for devolving powers to city-regions and combined authorities in the form of its New Deal of England – it is now vital that the party signals a long-overdue recognition that England-wide interests and identities need to be reflected and expressed in a reconstituted UK.

Embracing and owning this idea would also allow it to become one of the architects of reform, rather than a grudging bystander. This would also enable progressives to remake arguments for a wider constitutional refit, which would need to include the tabling of quasi-federal options for reform of the House of Lords. Labour will be forced to engage with these issues in a way that it hasn't had to before, whatever the outcome of Thursday's vote. And if the winning margin for a No vote in Scotland is small, the pressure for greater devolution of tax-raising powers to Holyrood than Labour has so far countenanced will be strong. This also has to mean revisiting the Barnett formula and grasping the nettle of devising a new, needs-based formula for distributing public expenditure more equitably across the UK.

Undoubtedly there is a whiff of the dusty and arcane about some of these options and the antinomian arguments they attract. This is partly because there is no such thing as a single correct answer to the English question. Just as important as a willingness to engage in policy thinking on these options is recognition of the need to establish a wider process of constitutional debate among the English – perhaps even a convention of people and politicians of the kind that has happened in post-crash Ireland – and also to create the will and momentum for significant devolution within England during the next parliament.

Over the past 20 years, a powerful feeling has gathered among the diverse peoples of England – especially those who live outside London – that they lack permission to assert their own democratic and national identity. In response to this, the political parties need to step up to the challenge of re-engaging the people as agents of their own constitutional and democratic future – just as has happened in Scotland over recent weeks and months. The democratic energy that has built up north of the border should not be allowed to dissipate. It needs to be harnessed to deeper projects of democratic renewal – and this means involving citizens, not just politicians. Ireland and Iceland have given us contemporary examples, but the English can invent their own own. If Scotland decides to stay in the union, the acid test for how politicians respond on Friday should be whether they recognise this, in their actions as well as their words.

Michael Kenny is a professor of politics at Queen Mary, University of London, and a visiting fellow at IPPR. His most recent book is The Politics of English Nationhood (Oxford University Press, 2014).