In the editorial for edition 19.2 of Juncture, co-editors Guy Lodge and Will Paxton ask what new ideas and alliances will emerge from this unprecedented period of uncertainty in Britain's economy and politics.

Since the global financial crisis struck in 2008, British politics has experienced a degree of uncertainty not seen since the 1970s. No political party commands the intellectual or political terrain, as the Thatcher and Blair governments did, and none can look to the future with unquestioned confidence. As yesterday's orthodoxies give way to new thinking, the chances of transformative change are the greatest for a generation - but only if progressive forces have the imagination and strategic ambition to grasp the moment.

This opportunity is largely the result of the Coalition government's failure to offer a way out of the economic slump. However, as Professor Tim Bale contends in our lead essay, another, deep-rooted explanation can be found in the generational changes that have shaped today's Conservative party.

The slow demise of the Tory left, Bale argues, has resulted in the party drifting towards the right, away from the centre ground. And a Tory party that increasingly regards Cameron as a Heath-like figure - maestro of the interlude, prior to the emergence and takeover of a Thatcher figure - will find it even harder to pull together winning electoral coalitions in the future.

This analysis suggests no room for complacency on the left, but such drift makes the prospect of a long-term centre-right realignment of British politics increasingly unlikely and reopens up political space for centre-left alliances.

Bale's analysis also provides lessons on how government by coalition can succeed - a vital issue, given that the first-past-the-post system is less likely to deliver stable one-party majorities than in the past. In Bale's view, the emasculation of the Macmillan, Heath and Clarke wing of the Tory party explains the Coalition government's woes: it struggles to govern well because it is nothing more than a marriage of convenience. Radical Lib-Dem 'Orange Bookers' are comfortable in accommodation with the Conservatives, but they do not represent the majority in their party.

Meanwhile, the demise of the 'One Nation' Tory tradition gives the Liberal Democrats few obvious allies with whom to make common cause. It is a coalition devoid of intellectual or ideological basis, increasingly tied together by the gossamer thread of personal empathy between its respective party leaders.

Yet this failure should serve as a warning to the centre-left. Without coherent ideological underpinning, any 'Lib-Lab' alliance after 2015 would be a long-term disaster. Trying, but failing, to govern through a mere marriage of convenience would set back progressive ambitions for a generation. Far better would be the development of a more politically robust and intellectually coherent liberal social democratic project, something discussed since the Edwardian period but never realised.

Such a task is immense. On issues like crime and civil liberties, the two parties are poles apart (and that is before you get to the parties' internal divisions on core issues). But opportunities exist. On social liberalism, the environment, Europe and internationalism, Labour and the Liberal Democrats have always been more natural bedfellows. And despite current disagreements on fiscal policy, the economy offers even greater potential for progressive forces to combine to address the great challenges of our times. Gavin Kelly and Nick Pearce, writing in this edition of Juncture, contrast a business-as-usual response to the crisis to one which reforms British capitalism - the second, bolder option is not only necessary, but could also provide intellectual foundations for a successful progressive alliance.

What Kelly and Pearce call 'fiscal realism' will inevitably be shared ground for both parties, given the spending constraints any future government will inherit. But it is reform of Britain's political economy - breaking up the big banks, supporting state capital investment in business, pursuing aggressive minimum wage policies, broadening the tax base (including wealth taxes) and developing new models of economic empowerment and ownership - which offers the greater promise. Any reform of Britain's political economy should draw on and enhance the major progressive traditions: it must combine a commitment to the historic social democratic goal of a fairer economy with liberal methods of empowering individuals, families and small enterprises.

A successful progressive alliance would also address Labour and Lib-Dem weaknesses. Labour would have to discard habits of kneejerk tribalism, step out of its comfort zone on issues like public service reform, and open itself up to ideas from different traditions. The Liberal Democrats could no longer obsessively prioritise esoteric constitutional matters and would have to connect liberal thinking to the critical challenges facing Britain today. As difficult as it might currently be to envisage, a Lib-Lab coalition, built on strong intellectual foundations, would therefore be a creative and powerful electoral force.

Amid the uncertainty and turmoil of the late 1970s, it was the New Right that successfully drew in other forces and developed new ways of thinking about the British economy and society. Today, presented with similar uncertainty, progressives must win the battle of ideas. This means rejecting business as usual and advancing a substantive reform of Britain's political economy which combines social democratic and liberal insights. When the electoral arithmetic points to another hung parliament, an intellectually coherent Lib-Lab coalition would not only make a virtue of necessity, it might prove to be the most effective way of securing lasting political change.