Veteran left-winger Jeremy Corbyn has won the leadership of the Labour Party by a landslide, taking almost 60% of more than 400,000 votes cast.
In a result which marks a fundamental change of direction for the party, the Islington North MP defeated rivals Andy Burnham, Yvette Cooper and Liz Kendall in the first round of counting, taking 251,417 (59.5%) of the 422,664 votes cast.
His victory was cheered loudly by supporters at the QEII conference centre in Westminster, who had greeted him to the event by singing the Red Flag.
After 32 years on Labour's backbenches, the 66-year-old won only a handful of votes from his fellow MPs but was swept to victory in the race to replace Ed Miliband by a surge of enthusiasm from members in the country as well as new "registered supporters" who paid £3 to secure a vote.
He now faces the massive challenge of forming a shadow cabinet which will deliver his anti-austerity, anti-war policies without splitting the party. Already senior figures including shadow chancellor Chris Leslie, shadow education secretary Tristram Hunt and Ms Kendall have said they will not serve under him.
Mr Corbyn must also prepare to face David Cameron in the House of Commons for his first Prime Minister's Questions on Wednesday.
Corbyn supporters chanted "Jez we did" as he took to the stage, putting on his glasses to deliver his acceptance speech.
Mr Corbyn said the campaign "showed our party and our movement, passionate, democratic, diverse, united and absolutely determined in our quest for a decent and better society that is possible for all."