What is Zac Goldsmith's pitch to London voters?

Mr Goldsmith increased his majority in Richmond and North Kingston by 19,000 at the general election

At the very point of his entry into the race for London mayor, Zac Goldsmith's decision revealed two big characteristics.

Only a politician with an acute sense of accountability would have sought permission to stand through a ballot of his constituency members in Richmond Park.

Only someone with his personal wealth would have been able to afford the estimated £60,000 cost of doing it.

Both characteristics could come to feature heavily in the months to come.

How rich he is doesn't just arouse that bit of Harpers & Queen curiosity that exists in many.

As Michael Bloomberg showed in New York, it can add volume to the voice of fearless independence seen as invaluable for earning a mandate from a capital city.

In the race for City Hall 2016, it might also revive some pretty basic class instincts and reinforce the starkness of the choice available.

Labour's candidate Sadiq Khan, not without strategic reason, began early to stress his humble origins.

Burden of wealth

A personal fortune of £200m may also help to frame an interesting perspective on the challenges ahead for the capital - as it faces more austerity and awaits the forthcoming Spending Review with some trepidation - and whether Mr Goldsmith can supply the answers as well as the empathy.

For that amount, you could pay for 1,000 police community support officers for four years, construct a new bridge across the Thames, buy 670 hybrid double-decker buses or install step-free access at three or four Tube stations.

But people who know him well say the burden of wealth can rest heavily on him and is a force motivating him to do good.

Labour candidate for London mayor Sadiq Khan is stressing his humble origins and pro-European credentials

Along with his environmental consciousness comes his desire to see more direct responsiveness to the electorate, which led him to champion measures making it easier to recall and unseat MPs for wrongdoing.

The letters pages of the local newspaper attest to his assiduous attention to his south-west London constituency - repaid with an increase of 19,000 in his majority in May.

Officials running key London services, whose brains he has picked these past weeks, say he is charming and decent.

With the charm, of course, comes some edge. He has a reputation for tetchiness with the media, and outright contempt for some sections of it.

Feeling wronged by an investigation into his election expenses in 2010, he embarked on a spectacular live on-air collision with Jon Snow of Channel 4 News.

Ofcom later backed the broadcaster.

Localism and liveability

Mr Goldsmith's reputation for independence, accountability and bloody-mindedness will be fully tested by what happens at Heathrow.

He has vowed to resign his parliamentary seat and cause a by-election if a third runway is approved. But if that decision happens as he is battling for City Hall, he has promised to remain in the fight as a Conservative.

Mr Goldsmith is adamantly opposed to a third runway at Heathrow

As to what else to expect on London's policy agenda, there are few details but there are overriding themes of localism and liveability.

There will be deep interest in how the son of the Referendum Party founder, Sir James Goldsmith, approaches Europe.

His opponent Mr Khan, who says how strongly he wants to stay in, thinks he knows what Mr Goldsmith's stance will be.

Newspapers point out the similarities with the current Mayor, Boris Johnson - Old Etonian, tousled blonde hair, previously magazine editors (in Mr Goldsmith's case the niche Ecologist magazine)

But the differences are just as pronounced.

On a leash?

Mr Goldsmith may lack Mr Johnson's wit, flourish and sense of the absurd. But he's interested in the detail, and will be unencumbered by newspaper columns and publishing deadlines.

Like Mr Johnson, though, Mr Goldsmith has called upon the services of Lynton Crosby, whose company CTF is already on board.

In 2012, Mr Crosby focused most of his firepower on engendering fear of a resurrected Ken Livingstone.

A strategy of keeping Mr Johnson on a leash and away from journalists was seen by some as jeopardising victory by cramping his style.

How comfortable would Mr Goldsmith feel in a straitjacket?

Might a few unrestrained flashes of Goldsmith anger enliven this contest - and pick up some votes?