Of all the Coalition’s many reforms one in particular unsettles both David Cameron and Ed Miliband. The innocent sounding measure also makes the future of the Coalition more fragile than it might have been. The new law was passed without the noise and fury that accompanied others, yet the change is proving to be an unexpectedly big leap into the unknown. No one in politics, the politicians or the media, has fully adapted.

The reform in question is fixed-term parliaments. Their introduction was supposed to stabilise the wild rhythms of British politics. For once everybody would know the date of the next general election years in advance and we could all calm down. The measure has had precisely the opposite impact, making this year in particular a precarious one for Cameron, a very tense one for the Coalition and a dangerously awkward time for Miliband.

Mortality

The current parliament is already nearing the end of its natural life. Symptoms of mortality take many forms. In terms of policy Cameron has made waves recently with two big announcements. Both apply to the next parliament and not this one. His proposals for a referendum on Europe and high speed rail take effect after the next election. The more immediate agenda in the Commons is of little significance compared with those post-election policies and the near revolutionary measures placed before MPs in the Coalition’s early unprecedented flurry of reforming zeal.

Only the innovative Speaker, John Bercow, ensures the Commons can still buzz sometimes with vibrant topicality by asking for regular ministerial statements on pivotal news stories of the day. The so-called Urgent Questions can disrupt ministerial diaries, but help make the chamber more connected with the real world. Most of the time, though, the Commons is nearly empty. The only recent excitement involved a vote on Tuesday about constituency boundaries for the next election, another signal that minds are moving beyond this parliament. Yet the election is more than two long years away.

The defeat of the proposed boundary changes is generating intense anger from Conservative MPs. They knew it was coming, yet the loss felt more painful when it happened, watching the perceived treachery of Nick Clegg and the Lib Dems as they voted with Labour to deprive them of seats next time. The tensions in the Coalition get deeper and this time the Conservatives are the wounded ones. The Lib Dems have been more often the martyrs to the Coalition’s cause, losing out on electoral reform and Lords’ reform. Now the Tories have  been dealt a terrible blow. This partnership formed over an economic policy that is not working is supposed to continue until 2015. It may have no choice but to continue, but a sense of a creative compact is fading fast with nearly half a parliament to run.

Meanwhile Tory MPs are getting more restive. Normally at this stage MPs’ attention turns to the next general election. Suddenly they discover a loyalty to their leader they did not know they had. Before fixed-term parliaments it was assumed that a Prime Minister would call a general election after four years. Even if it did not happen the assumption that it might would concentrate minds. After the first two years of a parliament a Prime Minister could calculate that at least an affectation of unity would replace insurrectionary instincts.

But this year is different. There will be no election in 2014. After the next 12 months there will be another whole year before the election moves fully into view. There is still plenty of time to be disloyal, to speak up for principled conviction, to plot and plan against a leader. This has some danger for Clegg. But Cameron is the main victim as news surfaces of a plot to install a successor (Adam Afriyie, pictured above) if he loses the election. Such plots happen for many reasons. One is that Conservative MPs have time on their hands, lots of it. They will rally round next year, but not this. The fixed-term has made prime ministerial life less secure rather than more.

Failure to adapt

Miliband struggles to make sense of the new rhythms too. He has been quite open about his reluctance to announce too much policy detail yet. He half-joked with me in a recent interview for a Radio 4 documentary “When I speak to previous leaders the one piece of advice they don’t give me is that I need more policy”. Miliband and his senior shadow cabinet members see little advantage announcing policies now, when the government can steal the popular ones and there is still half a parliament for the others to be scrutinised to the point where they become outdated or unpopular.

But the media fails to adapt too. When Miliband gave a New Year interview to the BBC virtually every question related to what his “tax and spend” policies would be at the general election. His refusal to make such commitments now looked evasive, even if it is impossible to take pivotal decisions when the economy could be in an entirely different place by 2015. Other shadow cabinet ministers wonder whether they should keep their powder dry given that there is so long to go, aware that if they do so they risk the persistent and lethal question: ‘How can you attack the Coalition when you don’t know what you will do?’

An effective line of attack from Cameron is to argue that on every front, from schools to hospitals, the Coalition is introducing radical change and no one knows what Labour would do about it. One reason for this, although in some cases not the only one, is that the long race towards the next election is only half completed and the Labour leadership want to be closer to the finishing line before declaring too much.

Constitutional reform only happens if it suits the interests of those implementing it. Presumably Cameron thought that in the unusual circumstances of a Coalition a fixed-term would bring stability. But most fixed-terms in other countries last a maximum of four years. Five years is far too long. And of those five this is much the most dangerous for leaders hoping to flourish when the still distant election finally arrives.