Labour has chosen a transport expert to fight Zac Goldsmith in the by-election he triggered in protest over Heathrow expansion.
Christian Wolmar, who has written a number of books on railway history, will stand in the Richmond Park contest on December 1.
The Conservatives are not putting a candidate up against Mr Goldsmith, who is standing as an independent, in the affluent seat that the Liberal Democrats are hoping to snatch back and Ukip have followed suit.
The Green Party said it would not enter the race and senior Labour figures urged the leadership to stay out of the battle to give the Lib Dems a clear run at taking it
But the local party picked Mr Wolmar, who has worked for charity Shelter and Camden Council, to challenge Mr Goldsmith.
He said: "It's a great honour to be selected to stand for Labour in the Richmond Park by-election which gives us an opportunity to expose the disastrous policies of this government and fight the third runway at Heathrow which I have long opposed.
"The Liberal Democrats and Zac Goldsmith supported every terrible decision taken by the last coalition government, from austerity to the unnecessary and expensive top-down reorganisation and creeping privatisation of the NHS. The Lib Dems are not a progressive alternative, but Labour is.
"Zac Goldsmith played a key role in the Leave campaign which led to the decision to take us out of the EU - a decision that 72% of voters here opposed. The only way to send a message to this government and that we do not accept what they are doing to our country is to vote Labour."
Meanwhile, the estranged wife of a government whip has launched her campaign to take the seat.
Fiona-Natasha Syms is standing in Richmond Park as an independent but said she would immediately join the Conservatives if she wins.
The Tory speech writer condemned Mr Goldsmith for throwing a "strop" by quitting and was unhappy when the Tories announced they would not stand. Within days she announced plans to throw her hat in the ring and has now launched a no-frills campaign.
She said: "Today I proudly launch my campaign in RPNK (Richmond Park). I'm running as an Independent but will immediately join the Conservative Party if elected.
"You matter. Your opinions matter. Your vote matters. It's about time you were put first. And I will do that.
"I'm running an expenses-free campaign. No fancy literature, no targeted ads, no gimmicks. I'll stand on a crate and make my case."
The candidate hit the headlines in 2013 after hitting out at David Cameron when he sacked Robert Syms from his job as a whip.
''PM just fired father of my kids over the phone," she wrote on Twitter. "Gave up chairmanship of a cttee to be a whip, worked hard and was widely acknowledged to be a good whip. He was utterly gracious and took it like a man, I am beyond furious. Loyalty counted for nothing.''
Mr Syms was made a whip again under Theresa May.
Mr Goldsmith campaigned for Brexit but voters in the seat overwhelmingly supported Remain in the referendum.
The Lib Dems are pouring resources into the seat in an effort to overturn the environmentalist's 23,015 majority on a pro-EU ticket.