Zac Goldsmith has overwhelmingly won the contest to be the Conservatives' candidate to run for London mayor in 2016, despite previously ruling out standing because people have had enough of "white male Etonians" in power.
The Richmond Park MP was backed by 70% of voters in an online primary to be the Tory to fight for the chance to follow Boris Johnson into City Hall.
Mr Goldsmith said he had been "obviously wrong" to previously rule out a run for the mayoralty on the basis of his attendance at Eton, the prestigious school which also counts David Cameron as a former pupil.
The MP, who inherited a fortune from his industrialist father Sir James, is an outspoken critic of expansion at Heathrow - like Mr Johnson - opposing a third runway at the west London airport.
He has also said he wants to ''mend our politics'', boost high streets, improve transport and provide a healthier environment.
If elected, the environmentalist is expected to step down from the Commons, triggering a by-election.
Mr Goldsmith said: "In the last seven years London has come a long way. Under Boris, London now leads the world in business, tech, media, art and culture - benefiting from unprecedented investment. It is why so many people want to live, work and do business here, and it is also putting increasing pressures on our city.
"We have seen record investment in our transport network, but we will need to continue that investment just to avoid grinding to a halt - while at the same time continuing to bear down on the cost of travel so that it delivers value for money for Londoners.
"Our living environment is facing increasing pressure, and we will need to protect, enhance and improve access to our green spaces, as well as radically improving the quality of the air that we breathe.
"But the biggest challenge of all is the housing crisis. Londoners are being priced out of their city and we will need a step change in the number of homes built, and the manner in which they are built."
Mr Goldsmith, whose father formed the eurosceptic Referendum Party, indicated he was likely to vote for Britain to leave the European Union in the referendum on membership.
He told LBC he would "enthusiastically" back David Cameron if he won significant changes during his negotiations but said he was "not going to tell you that's likely" and insisted he "wouldn't be bound by any kind of whip".
The mayoral candidate said border controls were one of the key issues that must be addressed in the talks ahead of the EU referendum.
His success comes after previously ruling out a run for the mayoralty.
At a Huffington Post fringe event at the Conservative Party conference in 2013, Mr Goldsmith described running for City Hall after Mr Johnson steps down as a "a suicide mission", adding: "The odds of my succeeding in the mayoral contest, I think people have had enough of white male Etonians, I'm not sure my chances would be very high."
But he told BBC Radio 4's World at One: "My assessment of the chances was obviously wrong. Obviously I want to do this."
Mr Johnson praised his potential successor, describing him as a "fearless" fighter who is "fizzing with ideas".
The mayor told the Press Association he believes Mr Goldsmith's environmental credentials will appeal to many voters.
"This is a guy who was the former editor of The Ecologist magazine who thinks very, very deeply about not just economic growth but how to manage economic growth in such a way as to continue to improve people's quality of life and not to destroy our wonderful planet.
"That seems to me is something a lot of Londoners will be very interested in hearing more about."
All Londoners on the electoral roll were able to vote in the primary, although those who were not members of the Conservative Party had to pay £1 to register.
Mr Goldsmith won 6,514 votes (70.6% of the total), with London MEP Syed Kamall in second place on 1,477 votes (16.0%).
Deputy London mayor Stephen Greenhalgh secured 864 votes (9.4%) while London Assembly member Andrew Boff came last on 372 (4.0%).
Mr Goldsmith will go up against Labour mayoral candidate Sadiq Khan in the vote next year.
Mr Khan said: "I welcome Zac Goldsmith to the mayoral contest and look forward to a positive and friendly debate about the big issues facing Londoners.
"This election is a referendum on London's housing crisis, and I challenge Zac Goldsmith to join me in opposing the Tories' Housing Bill, which will make our city's housing crisis many times worse."