The power of the trade unions in the last Labour leadership election, and the party’s near-total reliance on them for funding since, is well known. They voted Miliband in – despite the wishes of Labour members and MPs – and have since provided millions of pounds without which his party would have gone bust.

It’s generally assumed that those two elements – their leadership vote and their money – will continue to allow them to control the Opposition. But the election may well see the union barons become even more powerful.

McCluskey and his colleagues haven’t spent the last five years sitting on their laurels and enjoying the power they won in 2010. Instead, they’ve been working to consolidate their position. The leadership is decided by three blocks – the membership, the MPs and the unions. Rather than gamble that the next Labour leadership election can also be dominated by the union vote, they appear to be working to ensure that by the time it comes around they will control a hefty share of the MPs’ vote, too.

There are two approaches involved – the first is signing up or funding as many sitting MPs as possible, and the second is a well-organised campaign to ensure as many of their own activists and officials are selected as candidates in winnable seats.

If the strategy works, then even if their man is defeated in May they will be in a strong position to choose another left-wing nominee to replace him.

Let’s consider the numbers:

  • According to a Sun investigation a few weeks ago, 159 sitting Labour MPs are either Unite members or recipients of Unite funding. 128 Labour candidates are also Unite-linked.
  • The GMB website helpfully lists 87 MPs who belong to their union.
  • ConHome’s own study of the 45 candidates most likely to be elected in May found that no less than 40 of them (88.8 per cent) either work as union officials, received union backing in their selection battles or have since been given union money for their campaign.

Undoubtedly there will be more, as other unions are more discreet or less closely scrutinised – but for Unite alone to have the majority of Labour MPs on their books is in one way or another is staggering.

Their intent to increase their share of the Parliamentary Labour Party is clear, too. The 2011 Unite Political Strategy was leaked to LabourList a couple of years ago – its authors make clear their intent to “reclaim Labour” for the union through a combination of increased control of local branches, greater power over policy-making and the selection and training of a cadre of candidates for parliamentary office. The full political weight of the organisation was to be thrown behind the initiative in order to help win “the struggle for Labour’s soul”. This wasn’t about increasing their interaction with elected representatives, or about improving the social diversity of parliament, it’s explicitly about political control.

By June 2013 the strategy was proceeding apace. That month’s report by the union’s Political Director to the Executive Council, obtained by Mark Pack, states that “our political department work is dominated currently by candidate selection matters…That is our current priority”. The importance placed on getting their people selected was second to none – the report continues, “We have had to park some areas of work temporarily – selections wait for no-one.”

By this time, of course, the Falkirk scandal had hit the headlines. Evidently conscious of the increased scrutiny, the Political Director warns that he will not give a fully written report, lest it be leaked (a wise decision given that we are now reading it), but does go on to list 41 individuals whom the union is trying to help secure selection. That this was just a snapshot of the selection campaigns underway at that time, so it’s clear that the scale of the enterprise was sizeable.

We also know that other unions pursue similar programmes. The leaked documents mention requests from other organisations, including TSSA and Unison, that Unite lend its support to their nominees in some battles. The GMB has a section of its website dedicated to inviting members to join its professional training programme for would-be MPs.

Given the weakness of the current Labour leadership and the parlous state of the party’s finances, it’s clear why the unions feel that this is their moment to cement their control. All the signs suggest that they are succeeding in doing so. The interesting question is how this might affect Labour politics in the coming months.

The effectiveness of this strategy to “reclaim” Labour for the unions means that May will see a sizeable change in the ideological character of the Parliamentary Labour Party. If – god forbid – Miliband becomes Prime Minister then it’s hard to imagine him exerting any kind of lasting discipline over MPs who feel they owe their loyalty to a union boss rather than their party leader. Even Ed Balls’ reckless economic plans are too right-wing for the tastes of McCluskey et al, and they can be expected to apply considerable pressure to pursue a mythical alternative to spending restraint regardless of electoral or economic good sense.

If Miliband either loses in May or is unseated during the next parliament, then this new union powerbase among MPs will surely seek to anoint another representative of the left in his place. If it was possible for the unions to get their way in 2010 without the support of the parliamentary party, just imagine what they could do with the MPs dancing to their tune as well. Combine that level of influence with the fact that Labour’s financial position is unlikely to improve, leaving the party even more dependent on union cash – with strings attached – and the stage is set for a shift even further to the left.