Zac Goldsmith is an outsider. His independence from the party machine has helped to make him, according to a poll carried out in recent days by ConservativeHome, the front-runner in the race to become the Tory candidate in next year’s London Mayoral election.

That survey was only of party members, but at the general election, Goldsmith displayed his ability to reach a far wider public, by taking 58 per cent of the vote in Richmond Park.

His victory dispelled any remaining suspicions that he was a mere dilettante: a rich man attracted to self-indulgent green fads who thought it would be amusing to belong to the House of Commons.

When he was first elected in 2010, his languid manner did not at first dispel that illusion. Here was an MP who appeared to have all the time in the world, as he stood enjoying a cigarette at the foot of Big Ben, one of the few places in the Palace of Westminster where smoking is still allowed.

And those who did not know very much about him were perhaps aware that his mother had given her name to a nightclub, Annabel’s, while his father, Sir James Goldsmith, had engaged in an objectionable campaign to shut down Private Eye.

Sir James could be quite rude. During his legal battle against the Eye, he saw his friend, John Aspinall, offering a lift to Alexander Chancellor, editor of the Spectator, and Geoffrey Wheatcroft, and screamed: “Aspers! Keep away from those people! They are pus!”

No such stories are told about Zac Goldsmith. Even to journalists he manages to be civil. It is true there is a wonderfully entertaining ten-minute YouTube clip of him arguing with Jon Snow of Channel Four News.

But even as he calls Snow a liar and a charlatan, Goldsmith sounds polite. Without raising his voice, he confirms his reputation as an outsider, a man prepared to challenge one of the great television journalists of our age.

This willingness, in a polite yet persistent tone, to stick to his guns, became apparent during the last Parliament, and has won him the increasing respect of his fellow MPs.

They observe that he works hard: he is one of the dozen or so MPs who goes each day to the Commons Library to answer correspondence and deal with other reading and writing, with occasional excursions into the corridor to make calls on his mobile.

In his maiden speech, Goldsmith spoke of the need to rebuild trust in Parliament. He is a believer in direct democracy, including a recall mechanism by which voters can get rid of MPs in whom they have lost faith. He has campaigned for far tougher arrangements than the Government would like to see, which place much greater trust in the electorate

He has also said he will resign his seat if the Government approves the building of a third runway at Heathrow. Last week at PMQs, he challenged David Cameron on this subject.

Cameron treated him with marked politeness, plainly intent on not allowing the issue to lead to a permanent rupture. But whether or not it does, Goldsmith has shown he will put the interests of his constituents, and his own convictions, before the pro-Heathrow line taken by George Osborne and Sajid Javid.

As Jacob Rees-Mogg, a Somerset MP who favours Heathrow expansion – “You can build as many runways as you like at Heathrow” – says of Goldsmith: “It’s impressive how strongly principled he is even on things you disagree with him about.”

His constituents likewise praise him as principled. He became the Tory candidate for Richmond Park in an open primary held in 2007, and spent three years campaigning in what since 1997 had been a Liberal Democrat seat.

Goldsmith was on the Tories’ A list of candidates, and had been offered a safe seat in Hampshire. He was very tempted, but in the end decided his heart was in Richmond, where he had been brought up.

That was not the action of a career politician, who would have accepted the safe seat, regardless of whether he felt any commitment to the area.

After campaigning hard in Richmond for three years, Goldsmith won by 4,000 votes, which at the last general election he increased to 23,000 votes. He attends a very large number of local events, has developed an excellent rapport with his constituents, and insisted on balloting them before he allowed his name to go forward as a candidate for Mayor of London.

He is a delightful man to talk to, capable of listening as well as talking. He seems shy rather than bumptious. Although very rich, he is not addicted to luxury. Women are immensely keen on him: those in Boris Johnson’s office suggested, when the question of a Goldsmith candidacy first arose, that Zac should take over immediately.

Goldsmith has made the astute decision to announce that if adopted as the Conservative candidate, he will hire Lynton Crosby to run his campaign. For Crosby is already a winner: twice with Boris and once with Cameron.

Labour is alarmed by the prospect of taking on Goldsmith. His first career was as an environmentalist, which gives him good hopes of attracting green votes, including second votes from the Greens.

And Londoners generally like to vote for someone who is ready to stand up to Downing Street. Ken Livingstone attracted many votes from people who wished to register a protest against Tony Blair.

And Boris Johnson would never have beaten Livingstone without demonstrating a willingness, indeed a pleasure, in standing up to Cameron.

Tessa Jowell, who has the best chance of getting the Labour nomination, is by temperament a consensual figure, who wants to get on with the powers that be.

So although London is a Labour-leaning city, she might find it difficult to demonstrate as much independence of mind as Goldsmith naturally evinces.

Where does that independence of mind, that sense of standing slightly apart from things, come from?

He recently paid tribute to his father for founding the Referendum Party and thus keeping Britain out of the euro. He has also expressed admiration for his uncle, Teddy Goldsmith, who founded the Ecologist magazine, which Zac himself went on to edit:

Today we’re all green. But when Teddy started out, he was virtually alone. His was a decision to stand apart from his peers, risk marginalisation and even ridicule. But he never minded. When he was described by an Italian bishop as “the anti-Christ”, he was flattered. When President Suharto of Indonesia labelled him an “enemy of the state”, he wore it as a badge of honour. The insults went on and on, and he relished them all.

Part of the reason was that he was hard to pigeonhole. In some ways he was conservative; he had huge respect for traditional societies and he hated change. When I introduced glossy paper to the Ecologist, he thought it was outlandish. But he was also radical and courageous. Whenever the Ecologist was sent legal threats, his reaction was always the same: “Bring it on!”

But the most illuminating piece I read on the Goldsmith family is by Zac’s sister, Jemima Khan, and is about their grandfather, Frank Goldsmith. In 1910 he was elected as a Conservative MP. Although he was from a wealthy Jewish family in Frankfurt, he appeared in little more than a decade to have become fully assimilated into British society. Then the First World War broke out:

Frank Goldsmith, fervently patriotic, joined his regiment and prepared to fight. The old photograph, my father’s sole memento, showed Frank ready to lead the men of his district to war against the enemy. They were unaware he had been born a German and there was no reason why his past should ever have become public. But in the first few weeks of war, a telegram addressed to Frank arrived at the local post office in Bury St Edmunds. It came from his brother-in-law, Ernst von Marx, who was by now a respected senior civil servant in Germany. It was sent by ordinary mail, not through diplomatic channels, and the contents were read by everyone at the post office. “How can you consider fighting for anyone other than your fatherland?” Ernst asked. Within hours the news had spread throughout the constituency. Although Frank had never considered fighting for anyone other than Britain, and despite the fact that he had spent 10 years as a volunteer officer in his local regiment and was now a major, his constituents turned on him in a frenzy of spy mania. There were violent riots in Stowmarket. Protesters demanded that he be stripped of his commission and his parliamentary seat. In the villages around Cavenham, there were clashes between his supporters and his opponents. A bemused Frank found himself paying the hospital bills of the local men who had defended his house when protesters arrived with torches to burn it down.

Frank still fought for Britain at Gallipoli. But he stood down as an MP, and after the war he made a second life for himself in France, where he assembled a great hotel empire. He was still an outsider.

One reason why Cameron finds it hard, despite his recent famous election victory, to form a close connection with voters is that he is so very evidently an insider, who in the end can be expected to do whatever the Establishment regards as prudent.

It would burst the bounds of this profile to consider whether great leaders almost always possess, not just a willingness to challenge conventional wisdom, but some sense of being outsiders, which gives them an affinity with other outsiders, including ordinary people.

But one may remark, more modestly, that Goldsmith’s temperament, which is that of an exceptionally charming and even charismatic outsider, who considers it entirely natural to challenge existing elites, makes him a strong contender to be the next Mayor of London.