Andy Burnham said he would join Mick Lynch, the leader of the National Union of Rail, Maritime and Transport Workers, on the picket line.

"I don't see this as controversial - people are fighting for their incomes in a cost of living crisis. And so, of course, you've got to recognise the point that they are making," Burnham told Sky News.

The Labour mayor of Greater Manchester also called for the next prime minister to "get round the table" with unions to make "sector by sector deals."

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