In 2002 the first national firefighters’ strike in 25 years was called to demand a 40 per cent pay rise, which would have seen their salaries go up to £30,000 a year. Tony Blair compared the Fire Brigades Union’s leader, Andy Gilchrist, to Arthur Scargill; the local government minister Nick Raynsford said strikers were 'criminally irresponsible' for refusing to co-operate with an independent pay review. The dispute was eventually settled with a compromise pay rise of 16 per cent, tied to changes in working practices. In 2004, not long after the RMT union was expelled from the Labour Party for supporting candidates to the left of Labour in Scotland and Wales, the FBU cut its longstanding link with the party. Gilchrist was ousted as general secretary in 2005.

Last month the FBU held a recall conference in Blackpool to decide whether or not to reaffiliate to Labour. The overwhelming vote in favour was heralded by Jeremy Corbyn as a ‘milestone in the building of our new politics and our labour movement’. Gilchrist’s successor, Matt Wrack, said the most persuasive voices in the hall were previous opponents of the policy who had changed their minds since Corbyn’s victory. Some delegates said they were worried about the FBU being stuck inside in the party if the new regime were toppled. Wrack and others argued that Corbyn could only succeed if he had enough allies within.

Reaffiliation is also being urged by some activists in the RMT, and the leader of the National Assocation of Probation Officers told me he could foresee a push in his union too. Meanwhile Left Unity, the party set up by Ken Loach in 2012, has suspended electoral activity in recognition that Corbyn’s election ‘opens a new period of class struggle’. Salman Shaheen, the party’s principal speaker, said in his resignation statement that 'all those on the left should, like the hundreds of thousands who have already done so, join Labour to support Jeremy Corbyn and push for a Labour government in 2020.'

To shore up support, the FBU’s executive told members in Scotland and Northern Ireland that their subcriptions would not contribute to affiliation fees. But Scottish delegates to the recall conference told me that Labour was so toxic north of the border that any association would cause grief among the membership. At Blackpool’s Imperial Hotel, the Socialist Workers’ Party and Socialist Party were handing out leaflets telling delegates that they were better off supporting Corbyn without affiliating. As it happens, both parties have tried to get involved in local groups set up by Momentum, the new Labour left grouping; they have, however, been told to 'sling their hook'.

There are still questions for those who have fallen back on the parliamentary road to socialism. Campaigners for a more democratic and radical Labour Party have long voiced their frustration that unions’ actions do not match up to their rhetoric. Delegates from all but one union at Labour's policy forum last year voted against a proposal to commit to an anti-austerity alternative. Ken Livingstone has argued that unions push out-of-favour members towards party activity to keep them away from industrial work; reps are banned from sitting on both the Labour national executive and the TUC general council.

The past few years have seen a change of mood, however. Some unions nominated Corbyn for the party leadership despite the wishes of senior officials, but it would have been inconceivable for so many to have opted for a ‘hard left’ candidate ten or even five years ago. And the GMB, the biggest union to sit the leadership contest out, has recently elected a new general secretary, Tim Roache, who is considered a Corbyn supporter. Speaking after the vote, the FBU London region secretary, Paul Embery, said that firefighters were keen to involve themselves at all levels of the party, including going to branch meetings and standing for office locally. That sort of work will be essential for trade unionists who want to secure their role in the Labour Party; recent changes to party rules have watered down unions’ influence.

Wrack is aware of the danger. ‘Blairism couldn’t have got away with what it did without the unions,’ he told me. ‘There’s no way we’d go in other than to fight for our union’s policies. We’re not into doing any behind-the-scenes deals or to undermine the position of our members or rank-and-file trade unionists anywhere.’