The Peelites who repealed the Corn Laws, the Tory Democracy movement under Lord Randolph Churchill, the "YMCA" group of MPs in Stanley Baldwin's day, the Tory Reform Committee of the late 1940s, the Thatcherite insurgents of the 1970s, and now the Cameroon modernisers have all been revolutionary minorities within the party, yet wielding influence — except the Tory Democracy movement, which was routed — much greater than their initial numbers seemed to warrant. The fact that each of them except the Thatcherites hailed from the centre-Left or Left also says much about the inherent centrism of the party, and the constant magnetic pull exerted by the centre ground on Tory politicians over the centuries. In that sense both the premierships of Lord Salisbury, in reaction to the Home Rule crises and Gladstonianism, and of Margaret Thatcher, in reaction to militant trade unionism and hyperinflation, are the glorious exceptions in Tory party history, rather than the rule.

"Party trouble is the abiding headache of coalition government," states Harris, and if the testament of Tory party history is witness to anything it is that the Cameroons' greatest danger today comes not from the Lib Dems, or even from the electorate, but from the 81 Tory MPs who recently voted for a referendum to take advantage of the present Euro-crisis. "Cabinet government is, in truth, always more of a theoretical than a practical concept," believes Harris, but should the Cameroons cabal too much, or take their backbenchers for granted, or seem to over-appease the Lib Dems, nemesis can be waiting in the wings. My sense is that the Cameroons are very well aware of the tightrope every coalition must walk, and of the danger that all Tory leaders — barring Salisbury, Thatcher, Hague and Howard — have had to fear from the Right. (Of Iain Duncan Smith, Harris rightly states that he "was in receipt of a degree of publicly expressed contempt and disloyalty from his own people never previously shown towards a Tory party leader".)

Although Harris writes from an overall Thatcherite perspective — Ted Heath is accused of making "tritely mendacious assertions" in his 1970 manifesto — he is very restrained in his criticism of today's modernisers, who he believes dominate the upper echelons of the party but are not over-represented everywhere in it, especially at the grassroots level. He points out how David Cameron won a swing of 5.1 per cent against Labour in the 2010 election, the third largest since 1945, thereby gaining the party 97 seats. It was not enough, but it was a reminder of what a formidable vote-getting goliath Tony Blair had been in his day. This well-researched, highly readable and occasionally highly witty account should become the new standard history of the Tory Party, and required reading for all MPs, especially any tempted to believe that their party has a soul, let alone a conscience.