Rory Stewart, a former contender to be British Prime Minister, has announced he is stepping down as an MP and will be running for Mayor of London.
Mr Stewart said he would be standing as an independent candidate in the mayoral elections in 2020.
"I'm getting away from that gothic shouting chamber of Westminster, I'm getting away from politics which makes me feel sometimes as though Trump has never left London," he said in a video posted on Twitter.
"This is a city that is now in real danger, danger from Brexit, from technological change, but I think above all from what has happened in British politics, to the kind of extremism that is taking over our country."
I am running as an Independent candidate for Mayor of London, and here’s why.
— Rory Stewart (@RoryStewartUK) October 4, 2019
Please join me in my campaign: https://t.co/8y3xWpl9hY#Rory4London pic.twitter.com/jnaNy8IF0s
Mr Stewart, the former minister for international development, was one of 21 ministers to be expelled from the ruling Conservatives last month over support of legislation designed to avoid a no-deal Brexit. He remained a member of the party.
He will stand in the mayoral election next year against Shaun Bailey, the Conservative's candidate, and incumbent mayor Sadiq Khan.
Reacting to the announcement, Mr Bailey said he welcomed "any candidate’s decision to stand and hold Mr Khan to account over his woeful record in London".
Mr Stewart described his decision to leave the Conservatives as "painful", adding his departure was primarily down to the party's Brexit stance.
"I've been proud to be a member of the Conservative Party," he told London's Evening Standard. "There are many values I share with it. I parted company largely over Brexit and the tone of the party, which has become increasingly aggressive."
Mr Stewart, who served in the military and the diplomatic service before becoming a politician, saw his profile rise earlier this year when he stood in the Conservative Party leadership contest.
Much of his campaign centred around social media videos of Mr Stewart appearing in different areas of the country willing voters to come out and speak with him.
Now - if anyone is around and wants to talk - in Kew Gardens - for the next hour pic.twitter.com/E45A26Y5uR
— Rory Stewart (@RoryStewartUK) May 28, 2019
One of his videos sparked ridicule when Mr Stewart made the bizarre admission that he was pretending to film himself when asked by a journalist on Twitter.
He came down to the final five candidates before being knocked out of the contest, which was eventually won by Boris Johnson.
Before becoming an MP in 2010, Mr Stewart lectured at Harvard University and was a senior coalition official in Iraq during the invasion.
He is also an author, having written about his experiences of walking across Afghanistan in best-selling book, The Places in Between.
