The British are great ones for writing about people who might have made better prime ministers than the ones we actually got. In recent years, there have been times when it seemed that Larry, the Downing Street cat, might have been an improvement on the incumbent. Historians have tended to focus on Iain Macleod and Hugh Gaitskell, whose careers were cut short by early death, and Rab Butler, who was denied the premiership by the elders who, at the time, chose the leader of the Tory Party.  

Nigel Fletcher has turned away from this well-trodden road and taken a more literal-minded approach. He defines the ‘not-quite prime ministers’ as anyone who served as leader of the opposition, even if they served only briefly – for example, as a stop gap while a leadership election was taking place. This is an interesting exercise for two reasons: first, it turns the reader’s attention to the precise mechanics of how people come to be leaders of parties; second, it means that a group of partially, sometimes wholly, forgotten politicians who once stood briefly at the centre of the stage are brought back into view. We get, for instance, a chapter on Robert