We’ve become used to the suggestion that a Party leader’s “back story” counts with voters – that if he or she can demonstrate a “rags to riches” story, of which a state school education is an essential part, he will be more likely to be electorally successful.

It’s a claim that’s particularly pertinent to the Conservatives, given the long-standing electoral problem for them of being perceived as “the party of the rich” – explored repeatedly on this site by Tim Montgomerie when he was its editor.

But is it true that back story counts – and if so, how much?  For answers, one could plunge into the polling about the present Tory leadership contenders.  And we expect to do so soon.  But this morning, why look into the crystal when there is a book to read?  Why trawl the polling when one has recent history to draw on?

The Conservative Party’s leaders in modern times have been: Theresa May, David Cameron, Michael Howard, Iain Duncan Smith, William Hague, John Major and Margaret Thatcher.

Of these, no fewer than six of the seven received at least some state school education: May, Howard, Major and Thatcher were grammar school pupils; Hague was educated first at a grammar and then at a comprehensive; Duncan Smith at a secondary modern and then at a naval training school.

As for rags to riches and that elusive phenomenon, class, much must be left to the judgement of the reader.  Michael Howard’s parents were refugees from anti-semitism in Romania.  John Major is “the boy from Brixton” – the son of a former music hall performer and garden ornaments business owner.

At any rate, the most electorally successful of these leaders have been Thatcher (three election victories on the trot) Cameron (fought two, won one, lost none) and Major (fought two, won one, lost one).  Only Thatcher won a landslide – two, as it happens.  Hague and Howard both lost elections, and Duncan Smith never got to contest one.

So the only two Tory leaders not to have lost an election are a grammar school-eductated woman from Grantham and a privately-educated man from Berkshire – and an old Etonian, no less.  All in all, there’s no evidence that back story has made a difference to the electoral fortunes of Conservative leaders.

You may object that times have changed, and that “back story” is now more important, given the Party’s present electoral plight.  Or that one can’t test it in laboratory conditions – in other words, that the electoral success or failure of Tory leaders has depended on a lot more than their back story.

There may well be truth in these points.  But perhaps the last word should be left to Liam Fox – and his speech to the Conservative Party Conference in 2005, when he was a leadership candidate.

The front-runner in that contest was David Davis, whose camp made much of his own back story.  Davis was raised by a single mother in a council house, and educated at a South London grammar school, before going on to a successful career in business.

Fox’s conference speech that year was a success, Davis’s was not, and the former contained the memorable line, used often by Fox (who was also brought up in a council house, by the way) since: “we should elect leaders because of where they are going to, not where they have come from”.

It’s hard to argue with that view on the basis of the Tory experience in recent history.  As for Labour, it’s most successful leader in modern times was Tony Blair – the privately-educated son of a former Conservative Association Chairman.