Sir Keir Starmer has garnered the required support to advance to the final stage of the Labour leadership contest.
Having won the endorsement of the Union of Shop, Distributive and Allied Workers [Usdaw], Sir Keir had acquired the support of three unions and affiliate groups representing five per cent of the party membership, the amount needed to make it onto the final ballot.
The support of Usdaw comes after the Unison union and Labour environmental campaign group SERA had also thrown their weight behind the shadow Brexit secretary.
The MP for Holborn and St Pancras is the first candidate to reach the final stage, with Rebecca Long-Bailey, Emily Thornberry, Lisa Nandy and Jess Phillips the other hopefuls yet to win the required backing.
Usdaw general secretary, Paddy Lillis, said: "The Labour Party must be led by someone who can persuade voters that they have what it takes to be a prime minister and we are a government-in-waiting.”
Sir Keir said that he was “honoured” to have Usdaw’s support.
He said: "If I'm elected leader, Labour will stand shoulder to shoulder with the trade union movement as we take on the Tories and rebuild trust with working people.”
Usdaw has also endorsed shadow education secretary Angela Rayner in the race for Labour's deputy leadership.
The other contenders for Labour deputy leader include Ian Murray, Dawn Butler, Rosena Allin-Khan and Richard Burgon.
The unions, affiliate groups and CLPs must submit their favoured candidates for the party leadership by February 14, with GMB Union expected to make their endorsement on Tuesday.
On Monday, the deadline passed for new Labour members to join the party or any of its affiliated groups to be eligible to vote in the leadership contest.
The final ballot, which will be open to the party's wider membership, opens on February 21, with the new leader and deputy leader to be appointed on April 4.
