Rebecca Long-Bailey has scored a significant boost in her quest to become Labour leader after securing the backing of the Momentum campaign group.
The shadow business secretary – a front-runner in the race to succeed Jeremy Corbyn – won the overwhelming endorsement of its members in the result of the ballot announced on Thursday.
Though the result was not unexpected, the left-winger will now be boosted by the campaigning firepower of the group, which has long supported the outgoing leader.
Shadow education secretary Angela Rayner was also endorsed as deputy leader following the confirmatory ballot of Momentum members.
Ms Long-Bailey said: “Momentum members, alongside hundreds of thousands of other Labour members, worked day and night across the country to elect a Labour Government last December, knocking on millions of doors.
“I am proud and beyond grateful to be backed by an organisation that has revolutionised how we campaign.”
Momentum now plans to run “hundreds” of phone banks across the country and encourage supporters to use apps to make “hundreds of thousands of calls” to members in support of Ms Long-Bailey.
The campaign group said 70.42% of respondents voted in the ballot to approve Ms Long-Bailey, while 52.15% were in favour of supporting Ms Rayner.
There had been some controversy around the vote, however, with the pair being the only candidates in the yes-no question of whether Momentum should endorse them.
Each needed to win 50% of the vote so Ms Rayner only narrowly secured support in the ballot, which was responded to by 7,395 members.
The latest poll in the race put Ms Long-Bailey as winning the five-candidate battle to become leader, edging shadow Brexit secretary Sir Keir Starmer into second place.
The hopefuls are now in the second stage as they seek to make it to the postal ballot of members and other supporters.
They must get the support of 5% of local parties or at least three affiliates, including two unions, representing a 5% share of affiliated members by February 14.
The Transport Salaried Staffs’ Association plans to ballot members over whether to support Sir Keir or Ms Long-Bailey.
General secretary Manuel Cortes said both candidates “will make a great leader”.
Sir Keir has been backed by Unison and environmental affiliate SERA so only needs one more union to put him over the line.
Wigan MP Lisa Nandy has the support of the National Union of Mineworkers.
And the Bakers, Food and Allied Workers’ Union announced it would back Richard Burgon to be deputy leader.
Ms Long-Bailey – seen as the favourite of the current leadership – is to launch her campaign in Manchester on Friday, at a similar time to when shadow foreign secretary Emily Thornberry is expected to kick off her bid.
Birmingham Yardley MP Jess Phillips was also among the candidates to progress to the current stage after they won at least 22 nominations from Labour MPs and MEPs.
Meanwhile, the party revealed that around 14,700 people applied to register as temporary Labour supporters to vote in the leadership contest.
The 48-hour window to apply to be a temporary supporter closed at 5pm on Thursday, and applicants who meet the eligibility requirements will be able to vote in the leader and deputy leader elections.
The successor to Mr Corbyn, who led Labour to its worst general election defeat since 1935, will be announced on April 4.