David Cameron leads the only major British party to oppose a constitutional convention

Only Tories stand in the way of a British constitutional revolution

Only Tories stand in the way of a British constitutional revolution

Only the Tories stand in the way of a constitutional convention. If a vote were held in the Commons on this issue, there is a strong chance it would be approved. So is a petition of just 15,000 signatures really the best way of underlining its importance?

That is what will be handed into Downing Street today by organisers as they seek to bring about, in their own quiet way, what would be a massive moment in Britain's history.

The petition states:

"We the undersigned call on party leaders to set up a UK-wide Constitutional Convention to decide how the UK should be governed. The convention should be led by the people, not politicians, and should ensure fair and equal representation for the UK's nations and regions. It should decide the sharing of power between the four UK countries, and how power should be decentralised."

This is stirring stuff. If it happens, a convention of this kind would be an unparalleled victory for the campaigning organisations behind it – principally the Electoral Reform Society and Unlock Democracy, whose chiefs Katie Ghose and Alex Runswick are handing over the petition to Downing Street this lunchtime.

But they have a problem: 15,000 signatures is, in the modern world of e-petitions, not very impressive.

A quick glance at the e-petition website reveals a whole range of issues which have attracted more support. Eight thousand more people think there ought to be a recount of the Scottish independence referendum result. Twelve thousand more want to ban the sale of fireworks to the general public. Fifty thousand more want Britain to cease trading with Israel "until the Palestinians have their illegally stolen lands back". One hundred thousand more "oppose the proposed fees for nurses and midwives".

The reformers appear to appreciate this; they point to the distinguished credentials of some of their signatories, like constitutional expert Professor Vernon Bogdanor, and a range of civil society organisations, as if to compensate for the inadequacy of their mass appeal. The danger is that focusing on the petition risks ignoring the bigger picture: that Labour, Ukip, the Greens and the Liberal Democrats all agree on the need for a constitutional convention to happen.

Katie Ghose and Alex Runswick deliver the petition to No 10

"Fifteen thousand people signing up to this petition is a fantastic start and the momentum is really growing. This is just the beginning of the campaign," she told Politics.co.uk in Downing Street.

"It's exciting we've got so many of the major UK parties signed up to the idea of really strong citizen involvement in shaping the future of our constitution and the future of our democracy."

Runswick goes further: "Unlock Democracy believes this conversation is long overdue and it is not something which can be conducted behind the closed doors of a Cabinet committee meeting.

"There are already lively debates going on in communities across the country about where power should lie. We are calling on politicians to work collaboratively with the public in a constitutional convention to decide what’s next for the UK."

Labour's support for a convention is tainted by the suspicion it only wants one in order to kick the issue into the long grass. But the Lib Dems, who are actually engaging with the Tories in those secretive Cabinet sub-committee talks, have put a convention on the list of things they want to see. It might have been part of a big deal with the Tories, but that now seems unlikely. The government command paper now set to be published next week will merely include proposals from the two parties.

William Hague will make a statement to MPs on the government's command paper next week

This has all come as a little bit of a shock to campaigners. Now was supposed to be a quiet time for them after some big disappointments. The chance to change the voting system, viewed by many as the root of all evils in British political culture, was crushed early in this parliament by the alternative vote referendum defeat. The coalition's reforming zeal after the expenses scandal yielded precious few improvements, and those which did result – like the Fixed Term Parliament Act – have been dismissed as counterproductive. With the 2015 general election approaching, the expectation was one of very slow progress.

And then came the Scottish independence referendum. Not the thundering cataclysm of the end of the Union, but instead an extraordinary popular awakening north of the border which has echoed and resonated throughout the United Kingdom. It has, in truth, prompted a slow-burning constitutional crisis that will be resolved, one way or the other, in the coming months. Demands for English votes for English laws, matching or at least complimenting the new package of devolution to Scotland, is now intense. The status quo no longer seems tenable.

Will the Tories agree to a convention? It seems unlikely. But one overlooked comment from William Hague, who has been leading the Conservatives' search for an answer to the West Lothian Question, suggests agreement might be close after all.

Speaking on October 14th, as he rebuffed Labour calls for a convention as a "red herring", he did say this:

"There will be a place and a time for a constitutional convention, but not one that is simply a device to prevent those issues from being addressed now."

"A time and a place" – could that be in the next parliament? Perhaps next week's command paper might reveal more of the Tories' thinking. It could even be the breakthrough moment campaigners huddled outside Downing Street today have been searching for.

"William Hague has said he's open to the idea of citizen involvement in shaping the future of our democracy," Ghose added.

"After the Scottish referendum there are so many questions about devolution, about where power should lie both within the countries of the UK but also at local level as well. The message we're saying to all of the parties is that you cannot ignore citizens when it comes to these questions of identity and where power lies. It would be disastrous and illegitimate for the future working of our democracy if citizens weren't to be at the forefront of this change."

For Runswick, it's not about attacking the Tories. This is about something much bigger.

"We could just focus on getting the Conservative party to change their policy. But what we want to do is have a national debate," she said.

"You have to start from somewhere. So today was about saying 'this is the debate we've started, we've got all these people signed up, civic society and academics calling for this.' The ball is in your court. You can take action on this. You can open up debate beyond the Cabinet committee room and start a national debate about how we can be governed."