UNIONS use their collective voice to seek leverage. This is one of the essential strengths of the trade-union movement.

Unite set up an organising and leverage department in 2005 in order to develop a strategy for widening our traditional collective action going beyond our key terms, conditions and demands in the workplace to sector-based campaigning.

As a consequence of its successes, our bespoke form of leverage has been the subject of many attempts to declare it illegal. But how do you leverage an employer? What happens when everyday relations between an employer and their workers turn hostile?

To give one example, in the mid-2000s we identified the top four supermarkets that were refusing to accept a minimum-standards agreement for agency labour. We decided to find out everything we could about each of them: how they operated, their emerging markets and so on.

By doing that, we were able to lever them into the negotiating room. This was not about organising actions such as boycotts, choking supply chains or demonstrating outside AGMs, it was rather a tactic of “following the money.”

We committed ourselves to understanding everything there was to know about each company, just as they do when they make takeover and acquisition decisions. We did this so that when they told us they couldn’t afford a pay rise for our members because their margins were so small, we would know the truth.

Leverage will never be a substitute for strike action but it can be an extremely effective additional weapon in our armoury. When leverage and strike funds are put together, this demonstrates just how powerful a union can be in its determination to secure workers a bigger share of the profits they work so hard to achieve.

People have said that other general secretaries would not have taken the risks that I have with leverage. That may be true, but plenty of other unions have come to us, including sister unions in America and parts of Europe, wanting to adopt our model.

The most important aspect of what we are doing is that we are not scared to lose, because it is fear that mutes people. Leverage works alongside organising and it is important to explain that organising is not just recruitment.

Back in 1998 the TUC set up its organising academy, headed by the now TUC general secretary Frances O’Grady. Based on similar models in the US and Australia, it worked on the thinking that organisation needed to be built into a union’s recruitment strategy, in response to a dramatic decline in union membership.

A cadre of union organisers was brought in from the participating unions and sent on a 12-month training programme designed to give them the skills and experience needed to deliver effective organising campaigns and to empower members and activists in the workplace.

It was described at the time as an attempt to rediscover the “social movement” origins of the trade unions. My union was not involved with the academy initially but we did join up after Tony Woodley became general secretary.

He bravely created our own organising department, with a more muscular bottom-up strategy, putting organisers into workplaces, identifying leaders and then moving to the collective sign-up of thousands of people to the union.

We focused in particular on anti-union and non-unionised “greenfield” sites in the construction and manufacturing sectors. This way, we believed, the power lay with those workers who, organised in their workplace, could win on the issues that needed addressing.

In the first few years, we gained 69,000 members just through this form of organising. So, while organising does recruit people, it is primarily about building leadership structures and collective membership, so that all workers who join understand that being a part of the union reaps benefits.

The work unions are doing in the precarious gig economy is a perfect demonstration of this. While the gig workers’ voice is missing in so many of the debates about the relevance of trade unions to the modern world of work, we are empowering and giving a voice to those very same workers.

Unions give us strength, together, to fight bad bosses, and the results are palpable. In 2018, the Centre for Policy Studies chief Robert Colville claimed that unions showed a lack of gratitude to the government for “lifting” the cap on public-sector pay.

He accused the left and the unions, singling me out in particular, of using sleight-of-hand tactics to obscure evidence that public-sector pay has been growing faster than wages in the private sector. “You don’t see Len McCluskey going on TV and weeping crocodile tears for the underpaid private sector,” he complained.

Colville was blatantly ignoring the fact that I have spent all my working life fighting for decent pay and equality across all sectors of the economy and that my industrial background has been predominantly in the private sector.

Furthermore, his claim itself obscured a simple truth: union members in the private sector are getting better pay deals than those in non-unionised firms, multiple times a year. To give just a few examples: over a thousand workers at Pirelli Tyres received an inflation-busting 5 per cent pay increase. Unite and GMB members at the Rosyth dockyard working for Babcock engineering won a pay rise of at least £2,000, a 7.2-9.2 per cent increase.

Negotiations between union and management at 2 Sisters Food Group hammered out a 9.3 per cent pay deal. Low-paid Mitie workers at Sellafield in Cumbria — security guards, cleaners and vending, laundry and environmental operatives — won a historic pay rise of 55 pence an hour after a long and difficult dispute which, memorably, featured women strikers Zumba-dancing on the picket lines.

Clearly, being in a trade union benefits working people, including in the private sector. Our members consistently see a pay premium: we call it the union dividend. And it’s not just me who says that. Andy Haldane, chief economist of the Bank of England, confirmed that union membership is associated with higher pay for workers of between 10 and 15 per cent.

Gaining recognition, stopping people getting the sack, sorting out their grievances, getting them a pay rise, gives enormous satisfaction. Going back to members with a good offer and it being accepted makes you think: “That’s what my union is there for.”

My son Ian is now a union officer and he was overjoyed and emotional when, in one week, he stopped two people getting the sack. That’s why he’s a trade unionist.

Len McCluskey is general secretary of Unite the union. Why You Should Be a Trade Unionist is available at the special price of £5.59 from publisher Verso, versobooks.com