The vote came in response to a reorganisation announced by Labour’s general secretary David Evans last month, which will slash 90 jobs from the party organisation in response to a cash crisis.
Applications for a voluntary severance scheme closed on Tuesday and there are fears of compulsory redundancies if insufficient volunteers have come forward.
In an indicative ballot of party staff who are members of the Unite or GMB unions, some 75 per cent voted in favour of industrial action if faced with compulsory redundancies. Turnout was 80 per cent of the unions’ membership in the party.
Unite regional officer Matt Smith said: “Labour will be meeting with Unite and the GMB this Friday and both unions are hopeful that a way forward can be found that avoids any compulsory redundancies or resultant industrial action.”
The row comes ahead of a crucial annual conference for Starmer later this month in Brighton.
In his first major in-person address to the party since being elected last year, Sir Keir will try to shake off accusations that he lacks direction by setting out more details of his vision for the country.
But he is likely to clash with supporters of predecessor Jeremy Corbyn who blame him for the precipitous decline in membership numbers which has left the party strapped for cash.
And the new general secretary faces a potentially bruising bid to put his appointment to a ballot, with left-wing group Momentum urging supporters to back a motion to make his post a directly elected position.
Mr Evans previously served as assistant general secretary under Tony Blair, sparking accusations from Corbyn supporters that his appointment is part of a plan to drag Labour into the centre ground.
Under the banner Organise to Win, he has told staff that the party is adopting a new, slimmed-down structure, designed to produce “winning, voter-centric policies” rather than lecturing voters on what they should think.
Labour’s finances have also been hit by a number of pay-outs over anti-Semitism allegations dating back to the Corbyn era, while largest funder Unite is conducting a review of its donations to the party.
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