It is worth buying Reassessing New Labour just to read James Purnell’s short preface. New Labour’s would-be philosopher king pretty much disappeared from view after Labour chose the wrong Miliband as leader. Purnell’s piece highlights perfectly the challenge Labour faces in coming to terms with its 2010 election defeat. It is brilliantly lucid in assessing why Labour lost. It is extremely limited in its analysis of how to recover. In particular it completely ignores the 500lb gorilla in the corner – the economy. I’ll come back to this in a moment.

Diamond and Kenny’s book brings together a range of contributions from politicians, academics and ‘think tank-ers’. Curiously, some of the chapters that are most annoyingly partisan are not those written by parliamentarians or former parliamentarians. But the occasional burst of party bias is hardly surprising given the nature of the book and they don’t detract from its real value.

The editors set out their terms of reference precisely enough, as you would expect given their academic backgrounds. Their main aim is to ask why New Labour lost so much support between 1997 and 2010. They set out the scale of the party’s challenge in recovering from defeat but they stop short of seeking full-blown prescriptions for future victory.

Among the various contributions (which includes an interview with Shirley Williams), the chapter by John Denham is particularly insightful. His is one of the few that gets to the core of the problem with the whole ‘third way’ project. A political approach that is built on league tables, performance assessments and equality statistics will not reach an electorate that is broadly disinterested in politics. Indeed the complex (and usually outsourced) managerialism that became New Labour’s means of governing is likely to increase the sense of popular detachment from government. The politics of the shopping list will appeal to policy wonks like Thaler and Sunstein but it will leave most voters cold, even alienated, if they feel their party has lost its soul.

In the interests of disclosure, I first met Michael Kenny in Nick Clegg’s spare bedroom (inexplicably both Chris Bowers and Jasper Gerard missed that in their recent biographies). In a sense, he and his co-editor are archetypal Blairite academics. Not necessarily in their politics (though Diamond worked as a policy adviser for Blair and Mandelson) but in the way they approach their project. They carry their own ideological baggage lightly and understand the importance of effective communication (Tim Bale’s recent assessment of the Tory Party is in a similar vein.) This means that their slim volume is good value if you want to explore the reasons why Labour lost.

As for Labour’s future, let’s go back to the economy. Kenny and Diamond themselves point out the likely long term damage to Labour’s credibility that the debt crisis caused. They also hint at the deeper structural challenges that face a party of the left in the current climate. For decades Labour has aimed to pay for social policies out of economic growth. How does that equation work in a future of stagnation and diminishing resources? Even if the economy improves, can progressive policies cope with a globalised economy where capital and taxable income easily moves out and foreign workers easily move in?

The only answers Labour has come up with so far appear to have come from Maurice Glasman. Blue Labour, though seems to be even more of a throw-back to a lost age of class based politics where mobility and aspiration are excluded from the picture – precisely the analysis that landed Labour with eighteen years of opposition and ended with New Labour last time round…