We’re heading for a crisis in 2015 – whoever wins the election

There is something absurd about the Liberal Democrat conference, with all those attacks on their partners in government over the past four years. Such are the desperate tactics of a party crushed by coalition, one that has lost sight of its crucial historic purpose as it flails around for sustainable policies and fights for fourth place with the Greens. It offers little positive to the electorate, relying instead on the claim that it is nicer than the nasty party and safer with public finances than the spendthrift party.

Few tears will be shed if this short-sighted stance fails to pay off at next year’s general election. Nick Clegg’s self-immolating force is expected to lose half the 57 seats it won in 2010, which would be a good result since his party stands at six per cent in the polls at present. And in truth, these defensive tactics are no more reductive than those of the two main rivals, both restricting their appeal to traditional supporters rather than reaching out to new recruits.

This depressing focus on core votes threatens Britain with a dismal election campaign, which has now effectively begun following the party conferences. It is cause for dismay, given deep and often-deserved distrust for the political classes as the public watches them play anachronistic Westminster games. Yet the reality is the Liberal Democrats might still determine the nature of our next government after being heavily rejected by voters and shrivelling in size, which highlights the strange shape of current British politics.

As the Tories slip into a slight lead in some polls following a strong conference, few dare predict the result of May’s election. Labour benefits from an unfair electoral system, yet voters do not believe its floundering leader is up to the job of prime minister. The Tories have a strong economic message and leader, yet the electorate sees them as a party defending the rich and fears the health service is not safe in their hands. Meanwhile insurgent forces have arrived on the scene and there is no longer a simple binary choice.

Yet few ponder the potential implications of multi-party politics crashing against a creaking two-party system. Consider what might happen after the next election. It remains entirely possible for one of the two main parties to win outright majority – but it is likely to be a slender victory that leaves a leader held hostage by his ideologues and militants. This would not lead to good government at a time of intense domestic and global challenges; even right-wing Tory ministers have told me they dread such a result given the self-serving silliness of some on their fringe.

But it looks increasingly likely there will be another hung parliament. Put aside the reality that both main party leaders might face challenges in the immediate election aftermath, given existing hostility within their own ranks that would be fuelled by failure to achieve a majority. The biggest party might be able to form a simple coalition with the Lib Dems – but they may have too few survivors to make this feasible, forcing attempts to cobble together a government with the ragtag of other minority parties.

This possibility was highlighted last week by Peter Kellner, the perceptive president of YouGov, who concluded “the basic arithmetic is simple and devastating”. The number of Lib Dems must exceed the total of other minority party MPs to be certain of viable two-party coalition - yet such is their collapse, combined with the rise of nationalists in Scotland, England and Wales, that Clegg’s party could easily end up with barely half the 60-odd seats won by other smaller parties.

This would leave David Cameron and Ed Miliband scrabbling around trying to make post-election pacts with several partners. The Tories could offer an alliance on devolution with the SNP, who might surge to another 20 MPs following Labour’s lamentable performance in the recent referendum, or a deal on Europe to pacify Ukip, who seem set to win several seats. Labour might turn to the Greens if they keep their solitary seat, and Plaid Cymru, on course to pick up a couple more constituencies. Both parties would seek support from the 18 Northern Irish MPs.

If either leader is successful, we would be left with inherently unstable government held captive by smaller parties and its own extremists. More likely would be a short-lasting attempt at minority government, before The Queen is forced to call a second election; indeed, civil servants are already preparing for this possibility. If this ballot delivered a second unsatisfactory result, Britain would be engulfed in full-blown constitutional crisis – unless, of course, the two main parties swallowed significant personal and policy differences to form a Grand Coalition.

This rise of small parties challenging political certainties across Europe reflects the digital disruption engulfing societies. Yet no one should be surprised by this looming scenario – nor ignore the dangers at a time of contempt for mainstream politics. The share of vote won by the two main parties has been falling for six decades, yet Westminster has resisted radical reform. And the public usually gets what it wants at elections; last time round voters wanted rid of Labour but did not fully trust the Tories. Now there is one result the public wants above all – profound change to a political system that seems tragically stuck in the past.