It did not come as a surprise that Unite nominated Jeremy Corbyn for the Leadership of the Labour Party. There had been a high likelihood this would happen from the moment Jeremy made it onto the ballot paper.

The absence of surprise doesn’t make it any more palatable a moment though.

Unlike some commentators I am not moved to frenzy by this. Jeremy won’t win the leadership because you need 50% of the votes after transfers to do that, and it is difficult to see him picking up many second preference votes from the supporters of any of the other candidates. He will probably come third, and may come second, but apocalyptic visions of Corbyn-led Labour diving to 15% in the opinion polls are likely to remain subjects for dystopian alternative histories. As a democrat I want members to have Jeremy on the ballot paper as a choice. As someone who wants Labour to be in power, I definitely don’t want him to be the choice they make.

Nor am I about to rip up my Unite membership card in disgust. I’ve been a member of Unite and its predecessor unions and represented them as a CLP delegate since I first started work after graduating in 1993, I served on its predecessor’s regional political committee for a decade and was endorsed by them as a parliamentary candidate, and I would no sooner leave the Labour Party that leave my union because of a short-term burst of irrationality by its Executive. I believe all workers should be in the appropriate trade union, and in my case Unite was there to protect me and my colleagues at a PR company a decade ago when we faced a difficult round of redundancies. Whatever the daft politics at the top level, Unite performs its day-job of representing its members to their employers in a pragmatic and effective way. If you don’t like the choices it makes politically you need to be inside it as a member to change them in the future. Walking away just leaves the field to the far left.

But nominating Corbyn is so far from the politics of the predecessor unions as to be unrecognisable.

There is a proud and long tradition in the Labour Party of its affiliated trade unions acting as the steadying influence, the voice of pragmatism and moderation, the connection to the everyday concerns and practical politics of working people as a counterweight to the idealistic flights of fantasy of middle class party activists.

This was the role that Unite’s predecessor the TGWU played under Ernie Bevin and his two successors as General Secretary from the 1930s to the 1950s. Bevin, the scourge of the Communists in the union and the founder of NATO and Britain’s nuclear deterrent as Attlee’s Foreign Secretary, must be turning in his grave at Unite’s endorsement of someone with Jeremy’s anti-American, anti-nuclear take on foreign policy and defence.

The other component of the mega-merger that created Unite has a more recent history as the praetorian guard of the Labour right and played a major role in restoring Labour to electability in the 1980s and 1990s. Amicus was effectively a merger of two of the unions most sympathetic to Tony Blair. A previous merger had brought together the ferociously centrist EETPU (electricians and plumbers) and the AEU (engineers, many of them working in defence industries) to form the AEEU, led by Sir Ken Jackson, a leading figure in pro-Israel and pro-US caucuses within the unions. Both unions supported OMOV and the abolition of the block vote. The AEEU in turn merged with the MSF, a proudly white collar union created by the soft left Clive Jenkins but by the 1990s led by the moderate Roger Lyons and with an internal faction proudly badged as “MSF for Labour”.

You can trace almost every problem with the internal politics of the Labour Party back to Sir Ken Jackson losing his re-election bid in 2002. At this point the unions moved from being part of the dominant coalition running the Labour Party with Blair and Brown, to being a third force in between the leadership and the left. Now Unite has gone the whole hog and backed a Hard Left candidate for leader.

Jackson’s successor Derek Simpson blundered into a merger with the TGWU to form Unite which had not been properly thought through, because at some point in his youth in the Communist Party the line had been that mega-unions were a good thing.

Politically, it merged a union with a very pure form of lay-member-led internal democracy inherited from MSF with a brutal top-down authoritarianism on the TGWU side, where a dominant Broad Left faction had been trained for decades to obey instructions from paid staff or be purged. The professionally-led top-down authoritarians promptly purged the volunteer activist democrats, and were then, in the style of the “revolution devouring its own children”, purged themselves by successor generations of people even more subjugated to the machine, less independently-thinking, and more prone to shout vacuous slogans.

Beneath the veneer of a monolithic united machine, all committed to Corbyn and banging on about austerity, Greece, Cuba, Venezuela and Palestine, there are of course 1.4 million members whose views are rather more diverse. A very large number of them, 55% according to figures presented to Unite’s own Executive Council at Labour’s polling high watermark in 2013, are not even Labour supporters, let alone backers of Corbyn’s brand of impossibilist Marxism. The remaining 45% includes all the people like me who were happy with Sir Ken Jackson and Roger Lyons’ politics, and employees in such notable hotbeds of revolutionary leftism as the Barrow Trident submarine yard, the legal profession, the banks, and nuclear power stations. I do not remember being consulted about the Corbyn nomination but I would be staggered if it represents the politics of the median or even a substantial percentage of Unite members.

And industrially the merger made even less sense. Amicus was a clear voice for manufacturing and workers in the private sector. The merger with TGWU means though that Unite can often shout loudest about public sector issues, which is hugely duplicatory when Unison already exists to articulate those interests.

The Corbyn endorsement is not Unite General Secretary Len McCluskey’s fault. I am told he argued for the Executive to put head before heart and back Andy Burnham but lost by 34 votes to 13 because his own United Left faction had decided in caucus to back Corbyn.

I think some of the 34 votes would have been cast by people who are not Labour members and support far left political parties that have no interest in a Labour victory, such as the Communist Party of Britain, SWP and Socialist Party (AKA Militant). Why does Unite’s rulebook give the power to make Labour Party nominations to its Exec which is not exclusively Labour rather than its National Political Committee, which whilst also dominated by United Left is at least wholly Labour and elected by and from Unite members active in their local CLPs? We should have a system like Unison’s where only Labour supporters get to control the union’s relationship with Labour.

In policy terms, I completely get the logic that Corbyn is nearest to the policy positions of the union. But how did Labour moderates allow a situation to develop where our party’s largest affiliate has adopted policies so far away from the party’s own ones? Where were we when the far left hijacked the policy making of this great union?

Pragmatically I understand that backing Corbyn was helpful to winning votes at yesterday’s Unite Rules Conference against anti-Labour calls for disaffiliation. But again how did we get into a situation where we have to appease a ragtag and bobtail coalition of Trots and Stalinists by using the nomination of the country’s largest union for Labour’s Prime Minister candidate as a bargaining chip for keeping the union in the party its predecessors founded?

Nominating Corbyn is wilfully marching Unite in the opposite direction to the one that voters took at the General Election. Like Unite I backed Ed Miliband in 2010 but I have learned the lesson this May that even the vision Ed promoted and I believed in was too idealistic and fanciful for ordinary British working people, and that they demand a more pragmatic Labour Party, not the wish-list of causes advocated by Corbyn.

Even if you agree with Corbyn’s vision, large aspects of which I don’t consider any more desirable than they are realistic, you have to win elections to implement any of the things Unite wants to do for its members. Refusal to compromise with the electorate basically means the Tories get to kick trade unions and workers for five more years.

This nomination is bad for Labour. It gives the Tories plentiful ammo to fire as they resurrect the bogeyman of the “loony left”.

This nomination is bad for Unite. By backing someone who won’t win the leadership Unite will inevitably have less credibility and weight in the counsels of whoever does win, not to say less credibility with the workers it seeks to recruit and represent.

It is particularly bad for the link between Labour and the unions, adding to the friction, adding to a sense of growing distance between us just when we need each other most to fight against another five years of Tory cuts and privatisation.

It’s not tolerable to leave Unite with politics like this. Where are the Labour leaders who will follow the example of John Golding, who gave up his parliamentary seat to go back into his union, the NCU, as General Secretary, and will lead a fight back for the soul of our trade unions?

Len, I think you actually need help from people like me to defeat the people to your left.

To misquote my hero Neil Kinnock, I want my union back.