RAIL union RMT is backing independent candidate Jamie Driscoll in his bid to become elected mayor of North East England on May 2.
Mr Driscoll is the elected Labour mayor of North of Tyne but has been barred by Labour from standing as its candidate for the post in the enlarged constituency of North East of England.
He is standing against Labour’s Kim McGuinness.
RMT, which split from Labour in 2004, is donating £10,000 to Mr Driscoll’s campaign.
RMT general secretary Mick Lynch said: “Nationally, we need to put a Labour government in to get the Tories out, but we also need a strong voice that will put the north-east first, whatever government is in power.
“That’s why the RMT and our north-east region is completely behind Jamie’s campaign.
“I’ve always been clear about my politics — I believe Britain should be run in the interests of those who do the work.”