19/09/2013 13:14 BST | Updated 19/11/2013 05:12 GMT

A Political Flight of Fancy Perhaps, But Could 2015 Bring a British 'Grand Coalition'

There is a distinct possibility that this weekend's federal elections in Germany will deliver a repeat of 2005: no clear winner and a so-called 'Grand Coalition' of the centre-right CDU and centre-left SPD. While coalition is the normal state of affairs in Germany, the fact that once again the two main protagonists may be forced together must feel like an exercise in political sadism visited upon them by a disgruntled and uninspired electorate.

In Glasgow, meanwhile, and we have Nick Clegg's pronouncement that it would be far better for Britain if neither Tories nor Labour won outright in 2015 - and, by extension, that the Lib Dems should therefore continue in coalition, there to temper the baser instincts of its larger partner.

My question, though, is whether British voters might inflict the same political pain on the Conservatives and Labour? Is it inconceivable that we could see either David Cameron or Ed Miliband forced to form a government with his arch rival in two years' time? As political earthquakes go, this would certainly dwarf the result of May 2010.

The likelihood is remote, of course.

If there is to be a coalition, it remains more plausible that it will be the Lib Dems plus Labour or the Conservatives. That said, recent trends in British politics suggest a gradual but significant shift in the tectonic plates. Party membership is falling. Individual voters are increasingly concerned with a smaller range of issues about which they are more passionate. Some are even questioning the very utility of the mass membership political party. Were it not for the current first-past-the-post system, smaller more issue or agenda-driven parties like UKIP or the Greens would surely have broken through domestically.

The dominance of the two big parties remains because of our voting system. The consequence, though, is growing disenchantment with these parties as political institutions. Not only do they seem increasingly unrepresentative of the broader debates and trends within our polity, crucially they seem unable to react meaningfully to the challenges we face today.

In part this reflects an underlying consensus across 'mainstream' politics in favour of the free market, giving the impression that we no longer need 'big ideas' or 'big debates'. But increasingly, dynamic new movements and forms of political activism, such as 38 Degrees or Occupy, are emerging, enriching our civil society as they search for new ways to think about and address the political, economic and social challenges we face. In doing so, they are shining a light on the old, creaking political institutions, throwing their failings into sharp relief.

What does all this have to do with a possible British 'Grand Coalition'? Well, bar the outliers in each, currently there is little to choose between Labour and the Conservatives. An orthodoxy has emerged in which Labour is so desperate to regain economic credibility that it shies away from any meaningful challenge to the current government's austerity agenda. Meanwhile, for the Conservatives cutting taxes and spending has always been central to their political message. If we choose to punish the Lib Dems in 2015, we could end up in a situation where the two larger parties have no choice but to work together.

This may seem fanciful, but there is a serious point here. Our current electoral and party system has been on borrowed time for a while. We need to embrace the idea of coalition politics. And we need to have more players in our electoral system if it is to retain legitimacy in the longer term. This is the challenge we face as a 'mature democracy'.

The alternative, in 2015 at least, could be watching the excruciating discomfort on the faces of Messrs Cameron and Miliband at PMQs as they sit next to one another, being harangued by the leader of Her Majesty's Opposition...Rt Hon Vince Cable MP.