The Labour Party has given so many own-goals to the SDP this last twelve months that it is sometimes too easy to forget that the roots of the conflict go back far beyond the Wembley Conference in January and the Limehouse Declaration the next day. One-man one-vote, Tony Benn, mandatory reselection, and other Jesuitical niceties of Labour's internal arguments may have been the occasion for the launch of the new party (and what a wonderful occasion, save for those of us on the other side), but they were certainly not its cause.

The first value of Ian Bradley's well written book is that it reminds us that the schism which now looks as if it might rend the old Left apart has been on its way for a good twenty years or more. Twenty years ago Hugh Gaitskell and those round him