The Zac Goldsmith story

Zac Goldsmith has resigned as a Conservative MP, prompting a by-election, over his opposition to the building of a third runway at London's Heathrow Airport.

He's been promising for several years that he'll do it - and now he has, after the government backed Heathrow's expansion.

The south-west London MP, and long-standing environmental activist, feels the effect of such a huge project will be devastating.

There will be a by-election in the Richmond Park constituency that he has worked for years to transform from a Tory-Lib Dem marginal into one with a big Conservative majority.

There is bound to be plenty of razzmatazz surrounding the contest, but Mr Goldsmith - who ran unsuccessfully to be London mayor earlier this year - is hardly a stranger to it.

Born Frank Zacharias Robin Goldsmith in 1975, he grew up in Richmond.

His father was the flamboyant and domineering billionaire Sir James Goldsmith, who amassed a finance empire, along with three families and five homes.

His mother, Lady Annabel Vane-Tempest-Stewart, is the daughter of the 8th Marquess of Londonderry.

Her first husband was a nightclub owner who named the famous Mayfair club Annabel's after her, a hotspot not only for partying celebrities but also royals.

The pairing produced three children including Zac, who also has five half-siblings from his parents' other marriages.

His sister is Jemima Khan who was previously married to Imran Khan, the Pakistani cricketer-turned-politician.

She has also gained a high profile through her campaigning on human rights issues as a Unicef ambassador and over the phone-hacking scandal.

His brother Ben Goldsmith married and later divorced Kate Rothschild of the banking dynasty, but that was not the end of Goldsmith-Rothschild connection.

Zac Goldsmith married Sheherazade Bentley in 1999 and they had three children but divorced after he admitted to infidelity.

He went on to marry Alice Rothschild, his former sister-in-law, in 2013 and they now have two children.

In the past Mr Goldsmith has admitted he was no "monk", has struggled to give up smoking, and enjoys gambling.

The family have royal links.

They counted Diana, Princess of Wales, as a good friend and cousin Clio was married to the brother of Camilla Parker-Bowles.

Mr Goldsmith's father made his fortune in the corporate world, but also involved himself in politics.

In 1994 he launched the Referendum Party, with the sole aim of bringing about a referendum on the UK's European Union membership.

Sir James, who had been battling pancreatic cancer, died of a heart attack just weeks after the 1997 general election.

Zac Goldsmith was educated at Eton, from which he was expelled, and after spending time travelling and doing environmental work in the Himalayas, he returned to London and began working at the Ecologist magazine, which had been set up by his uncle, Teddy.

He ran it for nearly a decade and became owner and editor.

He combined his editing duties with running a farm with his first wife in Devon.

Despite his previously dismissive attitude towards the Conservatives, by 2005 he had changed his mind.

He joined and gave a speech at the party's conference in Blackpool, focusing on the environment.

He told party members: "A Conservative who is not also in his heart an environmentalist cannot legitimately be described as a Conservative."

Three days after David Cameron was elected party leader later that year, he appointed Mr Goldsmith as vice-chairman of a review of environmental policies that would influence the party's new direction.

In the 2010 general election Mr Goldsmith stood as the candidate for Richmond Park, an affluent south-west London constituency held by the Liberal Democrats since 1997.

A fierce battle ensued with insults slung by both sides. He won by 4,091 votes.

Mr Goldsmith has marked himself out as a big believer in direct democracy, advocating stronger powers for people to get rid of their MP.

His parliamentary amendment on the recall of MPs was rejected in the Commons but a government version became law in 2015.

In 2014, along with Tom Watson, now the Labour Party deputy leader, Mr Goldsmith made allegations about a Westminster paedophile ring and an establishment cover-up.

At the 2015 general election Mr Goldsmith kept his seat and managed to increase his majority hugely to 23,000.

After the prime minister announced the terms of his EU renegotiation, Mr Goldsmith - by then the party's high-profile London mayoral candidate - joined a number of senior Conservatives in coming out in favour of Brexit.

Despite his activism, his personal wealth, which he inherited from his father, has been the focus of much attention throughout his career.

In 2009, Mr Goldsmith faced criticism over his non-domiciled tax status, which he has since relinquished.

He inherited the status from his father and said it was not a choice.

People who are "non-doms" are allowed to limit the tax paid on earnings outside the UK.

But he denied he had been dodging tax, saying he had paid everything he owed in the UK.

In 2013 he said it would be "a suicide mission" to stand for mayor as "people have had enough of white male Etonians, I'm not sure my chances would be very high."

But later that year Mr Goldsmith seemed to have changed his mind, saying he had opted to run after being urged by people "from across the political spectrum" to stand.

The campaign to become mayor was bitterly fought, with Mr Goldsmith's affable demeanour lent some bite by Sir Lynton Crosby, the political strategist who ran both of Boris Johnson's campaigns and the Conservative 2015 general election campaign.

It was condemned by rivals as a "divisive, dog-whistle campaign", with Mr Goldsmith accusing Labour's Sadiq Khan of giving "platforms and oxygen and even cover to people who are extremist".

Mr Khan won by 56.8% to 43.2%

During his time as an MP Mr Goldsmith has been proud of remaining independent-minded, and the cause he has pursued most vociferously is his opposition to expanding Heathrow Airport.

In 2012 he said he would resign as an MP if it went ahead.

Now it has, and Mr Goldsmith has honoured his commitment to stand down.