Two more apparently different characters would be hard to imagine. Jack is a tie-less, bearded new university lecturer in his 30s. For him politics has been a passion ever since he left his north of England working-class home to go to university. Henry, meanwhile, is enjoying retirement in the quiet village he and his wife discovered as he came to the end of a distinguished career in the Army. He and his friends often discuss how best to put the world to rights, but they only talk "common sense", not politics.
Yet Jack and Henry have one vital quality in common. They are the lifeblood of our two main political parties. Jack and his friends are the mainstay of their local Labour Party. Henry and his social circle are naturally all Conservatives. Neither of their parties would survive for long without people like them.
Yet the Jacks and Henrys of Britain also sometimes appear to be a threat to their parties. In the 1980s Labour Party activists such as Jack seemed hell-bent on bringing their party to its knees as they called for nuclear disarmament and then tried to ensure that every Labour MP toed the party line by putting them through mandatory reselection. But the party's internal strife helped consign it to four general election defeats in a row.
Twenty years on, the fate of the Conservative Party now appears to lie in the hands of Henry and his ilk. Tomorrow a ballot paper for the Tory party leadership should arrive on Henry's doorstep. For the first time, every Conservative Party member in Britain has a chance to say who should be their new leader.
On the face of it they appear to have a choice between one candidate with the public appeal and charisma necessary to lead the party out of the electoral wilderness and another who, while he may keep the true blue flame of Thatcherism burning, looks to be as unattractive to the wider public as the previous incumbent, William Hague.
That at least appears to be the message of the opinion polls. If any group of people in Britain other than Conservative members were to be asked who should be the party's next leader, there seems little doubt they would choose Ken Clarke. However, Conservatives themselves are apparently inclined to opt for Iain Duncan Smith. For example, Mori recently found that among voters as a whole, Mr Clarke leads Mr Duncan Smith by 46 per cent to 20 per cent as the person who would do the best job as Tory leader. Equally, an ICM poll on Sunday found that more ex-Tories said they would be more likely to return to the fold if Mr Clarke were leader than if Mr Duncan Smith won the contest.
Yet every attempt to establish what Conservative members think has put Mr Duncan Smith ahead.
Surveys of constituency chairmen have typically found that for every two backing Mr Clarke three are supporting Mr Duncan Smith. A Mori survey of 100 ordinary Tory members in Cambridgeshire North East gave Mr Duncan Smith a 3 to 1 lead. Meanwhile, a phone-in poll organised by The Daily Telegraph procured an astonishing 8-1 lead. However, whether these polls really tell us what the Henrys of the Conservative Party are thinking is open to doubt. Henry is not a party activist like his constituency chairman, and does not respond to phone-in polls. Whether he thinks like the relatively small number of members in one little corner of England is a moot point too.
In truth we are unlikely to know Henry's mood until the result is announced on 12 September. No pollster has access to the list of Conservative members entitled to vote. So no one has had any way of selecting a representative sample of Tory members to gauge their views.
But would ordinary party members necessarily be consigning their party to third place behind the Liberal Democrats, as Francis Maude suggests? One simple reason for Mr Clarke's greater popularity among the general public is that he is better known. Few people outside SW1 and the Conservative Party had even heard of Mr Duncan Smith before the leadership contest began last month. Meanwhile, Mr Duncan Smith's stance on the single European currency can hardly be likened to that of Labour's far-left on nuclear disarmament in the 1980s.
Electing Mr Duncan Smith would not so much be foolhardy as a risk. In the wake of his election, the largely vacant image of him in the public mind would begin to be filled rapidly. This may be for good or – as largely happened to William Hague from the moment he went down a water slide in a baseball cap – for ill. But any ill impression that takes hold in the early days will not be easy to change.
In the end, however, it is not so much the personal image of the two contenders that matters as the strategic direction they would give their party. So far the debate about how the party should respond to its second landslide defeat has focused on how it can best regain the six million votes it has lost since 1992.
Yet this debate misses a crucial point. In terms of votes, the Conservative defeat in June was only marginally worse than that suffered by Labour in 1992. What turned it into a landslide was the electoral system. The Conservatives lost out because Labour successfully focused its efforts on winning votes in seats in Middle England while maintaining the informal coalition of anti-Conservative tactical voting created in 1997.
Unless this pattern is reversed, the Conservatives could lose the next elections even if they recaptured many of their six million lost votes. Yet it is not clear that either leader candidate has a strategy for doing so. But then, as Michael Portillo discovered, telling your party where you propose to take it is not necessarily the best way of winning a leadership election. Even Tony Blair only said he wanted to scrap Clause 4 after he became leader. Perhaps, after all, the best that Henry can do for his party is to follow his instinct – whatever that may be.
John Curtice is Deputy Director, ESRC Centre for Research into Elections and Social TrendsReuse content