Iran Press/Europe: Starmer won 275,780 votes out of 490,731 returned votes - equivalent to 56.2%.
Long-Bailey won more than 27% votes, while Nandy who came third secured just over 16% of the ballots.
In 2015, Jeremy Corbyn took almost 60% of the vote.
Although the result marks a significant change of direction for the party, with a move away from the politics of Jeremy Corbyn, Starmer paid tribute to outgoing leader and said he would work to stamp out anti-Semitism in the party.
He said: "I want to pay tribute to Jeremy Corbyn, who led our party through some really difficult times, who energized our movement and who's a friend as well as a colleague.”
Corbyn had said after the defeat in the 2019 election that he was ready to step down as party leader.
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