This book asks a question to which many of us would welcome an answer: "What are the philosophical roots of new Labour?" In the end, the search has to be declared unsuccessful - but the fascination of the journey is more than adequate compensation. Diamond, a former adviser to Tony Blair and now working for Alan Milburn, has assembled a collection of "revisionist" Labour writings - by authors from R H Tawney to Gordon Brown - which together tell a compelling story of the party's difficult 20th century.
The themes that animate the collection are the attitudes of the party towards Marxism, public ownership and the market. A crude summary is that the revisionists gradually weaned the party off class-based analysis, away from nationalisation, and towards a full-blooded embrace of the market. Diamond perhaps focuses a little too much on these themes, to the neglect of other revisionist agendas such as nuclear disarmament, Europe and women's rights, but the basic argument is sound.
Diamond endorses the view of Anthony Crosland, who wrote, in The Future of Socialism (1956): "The worst source of confusion is the tendency to use the word [socialism] to describe not a certain kind of society, or certain values which might be attributes of a society, but particular policies which are, or are thought to be, means of attaining this kind of society or realising these attributes." In particular, Labour became obsessed with the idea that nationalisation was the path to social- ism - which is what made junking Clause Four such an important symbol ("like taking Genesis out of the Bible", according to Harold Wilson). Diamond aptly describes the final moment of rewriting as "signalling the triumph of the revisionists in the battle for the party, delayed by 35 years".
Diamond shows how Crosland, Hugh Dalton, Denis Healey, Roy Hattersley and others helped the party to rid itself of its nationalisation fetish and embrace equality as the goal of socialism. And he is right to criticise the recent leadership for overdoing the "newness" of new Labour at the cost of being unable to connect the modernisers' battles with a rich seam of the party's history: as he points out, Gaitskell is virtually invisible in new Labour texts. "In the early days of 'New' Labour, the party's hierarchy perceived that proximity to revisionist social democracy damaged its cause," he writes in his introduction. In fact, the desire to detach Labour from any kind of history was even stronger than that: it was, after all, Diamond's old boss who declared that new Labour was "literally, a new party".
The collection also reminds us how today's keepers of the flame are often yesterday's revisers. Hattersley, who (to Diamond's regret) is now at perpetual war with the leadership, shifted the party towards a more pro-market position in his essay "Choose equality" (in Choose Freedom: the future for democratic socialism, 1987). Yet the essay shows how far the benchmarks have moved. In this "revisionist" tract, Hattersley urged the party not to shrink from the "assault on private medicine and private education", and assured readers that a "socialist government committed to real equality will clearly embark on a massive programme of redistribution". It is difficult to imagine the words "massive" and "redistribution" being used in such close proximity today.
But Diamond cannot provide a philosophical guide to new Labour by ransacking the treasures of the past. A philosophy has to show not only where you have come from, but where you are going. Since revisionism can only ever perform the former task, it is not a sufficient basis for a sustainable ideology.
There is one chilling message here. The general view is that the party had to adapt itself to Thatcherism. But Diamond suggests that Labour had the opportunity to reform in the 1970s and therefore head off the worst of the 1980s restructuring. To that extent, old Labour has to bear some responsibility for the "firestorm of Thatcherism".
Diamond ends his introduction by issuing a challenge for the future. He points out that revisionism is a "cast of mind.[with] the revisionist account of one generation the orthodoxy of the next, requiring a new revisionism to test it against changing circumstances, keeping ossification at bay". It is surely safe to say that Blairism is the orthodoxy of this generation. So who are the revisionists now?
Richard Reeves is director of Intelligence Agency (www.intelligenceagency.co.uk)