Some days you get a glimpse of what trade unionism could be. Earlier this year, I met Lewis and Shen, two of the young workers who have taken on the might of McDonald’s. Their energy and determination is inspiring.

But Lewis and Shen are unusual. They are active trade unionists in their twenties. And they work not just in the private sector, but in one of its highest-turnover industries – hospitality.

Too few young workers are in trade unions. And yet combining with their colleagues in a union is the most powerful tool working people have at their disposal. Collective organising gives ordinary working people the power to force their bosses to the table and make them negotiate.

And that’s what unions have done, for nearly 200 years. But now, with membership falling, particularly in the private sector, we need to work out how we reform trade unionism for the 2020s.

Too many private sector and younger workers don’t think of unions as representing people like them. They have never met anyone who is in a union. The slow pace of union digital adoption puts us out of contention for the attention of those we want to join. And above all, we do not have a compelling proposition of trade unionism for people who don’t work in an already-organised workplace – which includes most private sector workers.

Plus, capital is changing. Business models are changing. And working lives are changing too. It’s not the case that work is suddenly fair and well-paid for everyone. Trade unions should be part of fixing the new forms of exploitation we see. But unless we change our movement, we won’t be.

That’s why I am delighted by the publication of a new edited collection: A New Collectivism. All the contributors are champions of a strong and effective private sector trade union movement. Some ideas may feel uncomfortable. But that is a plus: we should spend more time thinking and working out how we build an offer that will help us recruit more private sector workers.

The last few years give me hope. We have seen an upswing in union organising in high-profile workplaces. At Sports Direct, Unite are steadily increasing their membership – and they have already won higher wages for the staff, started agency workers on the path to permanent jobs, and dragged the boss to parliament to explain himself. GMB have won a series of victories proving that so-called self-employed drivers in private hire and delivery are in law workers who are entitled to holiday pay and sick leave. Usdaw, organising in the high-turnover retail sector, have to run fast to stand still – but they now increase their overall membership every year. Bectu’s innovative organising model in the entertainment industry helps self-employed skilled technicians negotiate fair rates for everyone.

And the TUC is getting behind union organising too. We train thousands of workplace reps every year, to help unions develop smart strategies that bring the benefits of trade unionism to unorganised workers. For the past six months we’ve been working with two unions to pilot a new joining journey to get non-traditional workers into trade unionism.

Our biggest priority is organising young private sector workers. Our programme is being co-created with young private sector workers themselves. After a year of research and development (which you can read about at tuc.org.uk/ building-stronger-unions), we’ve begun to prototype a model of trade unionism that appeals to young workers and is tailored to their lives. The offer will be built around the union movement’s traditional strength of helping people get on in life. It will give a new way in to trade unionism, one which we hope in the long term will deliver the benefits of collective bargaining to the under-30s. I look forward to launching a full pilot during the TUC’s 150th anniversary year, 2018.

The founders of the trade union movement took on the cosy consensus of their day – that bosses could do what they liked with impunity – and proved them wrong. Now trade unionists need to innovate to take on a new generation of bosses who believe that collective power among working people is a thing of the past. As the former Scottish miners’ leader Mick McGahey once said: “We are a movement, not a monument.” It’s time for a change.