Although a Yes vote would have meant a very obvious change to the existing constitutional structure of the UK, the consequences of the No vote will still be complex and profound. The outcome has already put contentious issues such as the West Lothian question back on the agenda, writes Meg Russell.

This article originally appeared in the Observer. A version is available on the Guardian website.

The constitutional consequences of a Yes vote in Scotland would have been momentous, leading to months – possibly years – of fraught negotiation with uncertain consequences. But the consequences of no for the rest of the UK may, paradoxically, be even more complex and profound.

Since establishment of the Scottish Parliament in 1999 the ‘West Lothian question’ – Scottish MPs voting on legislation not affecting Scotland – and wider ‘English questions’ have rumbled on but rarely reached centre stage. They were temporarily sidelined by announcement of the independence referendum. Had Scotland voted yes, their urgency would have declined. Controversies over Scottish MPs at Westminster would clearly have ended with their departure, however painful that might have been.

A No vote was always going to put these issues back on the agenda, particularly because the status quo ante was not an option. Under the Scotland Act 2012, a No vote was already to hand substantial new powers to the Scottish Parliament, particularly over taxation. During the campaign, political leaders went far further, promising additional devolved powers including on welfare and tax. This has angered Conservative MPs.

While the new powers to be devolved remain unclear, increasingly lopsided arrangements between Scotland and the rest of the UK (particularly England) sharpen the West Lothian question. David Cameron drew particular attention to it in his first post-referendum statement, while William Hague (who will chair government discussions) called it ‘indefensible’ for Scottish MPs to continue to vote on English policy.

If these issues cannot be resolved, there are real dangers of an English backlash (leaving aside the complication that Wales wants more devolution too). The uglier side of English nationalism has so far been largely kept at bay and it needs to remain that way. Scottish nationalists, meanwhile, are bruised: politicians cannot now renege on their promises to Scotland.

Yet the constitutional problems presented by the West Lothian question are complex, as academic studies show. Some – including Will Hutton recently in the Observer – suggest that full-blown UK federalism is the answer. But his proposal that a reformed House of Lords should bind the federation together illustrates the challenges posed. The US and Australian federal second chambers weight each state equally; England, with 85% of UK population, would never tolerate that. Yet lack of popular demand makes nine new English regional assemblies – particularly with powers equivalent to the Scottish Parliament – unlikely.

More pragmatic solutions mooted include an English parliament (most vocally this week by John Redwood) or some variation on ‘English votes for English laws’. Though the latter appears more minimalist, it adds up to the same thing. Teasing out ‘English-only’ bills is technically pretty challenging, but might help somewhat. The real crunch comes though when the UK elects a government that needs Scottish MPs’ votes for its majority – as in 1964 and 1974. This could necessitate forming an England-only government of a different political hue inside Westminster: an English first minister, English cabinet and English parliament in all but name. The politics are crucial: Labour is the party most likely to be denied its majority, the Conservatives the likely beneficiaries. But more fundamentally, the English have not asked for an English parliament. For them to get one unexpectedly via the back door of ‘English votes on English laws’ – perhaps as early as May 2015 – would seem anomalous.

This leads to another proposal for which demand is growing: some kind of constitutional convention. A wide-ranging UK convention would likely fail, lost in a mass of competing proposals. But a narrowly focused convention on territorial matters might have benefits, especially if created quickly. Including randomly selected citizen members (as Ireland’s recent convention did) could help escape entrenched party positions. They might even come up with something new: four or five bigger English regions? But even if it failed to resolve the central questions, a serious and well-designed convention could at least ease immediate tensions and expose citizens to the intractability of the issues. Otherwise, failure to respond adequately to devolution risks becoming yet another charge laid at Westminster politicians’ door.

Meg Russell is deputy director of the Constitution Unit, School of Public Policy, University College London.