Labour MP Sarah Jones has taken the seat in Croydon Central from Conservative Gavin Barwell, winning a majority of 5652.
Mrs Jones gained 7285 votes to gain a grip on the hotly contested seat after missing out in 2015 by just 165 votes.
Mrs Jones ran a people-powered campaign to win over voters and said Mr Barwell had broken promises in his time as MP.
In her acceptance speech she said: “Young people won this election.
“They came out for the first time and they wanted to vote. They wanted to vote for Croydon, for their constituency, and for their futures.
“Young people are enthusiastic about politics which is extraordinary, they are usually so apathetic.
“Young people are taking back control and I think people began to see the honesty of Jeremy Corbyn’s campaign”
“It is a vote for hope.”
Mr Barwell, who was Minister for Housing, said: “If there is one upside it is that I will get to see more of my children and give them the time that they deserve.
“I think demographic change has definitely been a factor over the past 25 years but tonight has been a very special result.
“It was an election that was focused around the Brexit issue and London was one of the only parts of the country that voted heavily to remain so clearly we’re going to have to look into that.
“I think the party really needs to take a careful look at itself to decide how we will learn from this and how we will recover from this.
“We have crucial local elections coming up next year and I am determined to see Conservative council in Croydon and I’ll still be actively involved campaigning with my colleagues who worked so hard for me.
“One of the things I said in my book is that what you do locally can make a difference if it’s close but if the tide is against you, it’s still not enough.”
Sarah Jones (Labour) 29,873 ,Gavin Barwell (Conservative) 24,221,Gill Hickson (Liberal Democrat) 1083, Peter Staveley (UKIP) 1040, Tracey Hague (Green) 626, John Boadu (Christian People’s Alliance) 177 ,Don Locke (Independent) 71.
Labour hold, majority 5,652