Last week, a Freedom of Information request revealed an historic no-strike deal between the trade union GMB and outsourcing conglomerate G4S. This isn’t surprising, given the decline in union membership and power over the past 40 years due to deindustrialisation and legislative attacks. Today, many unions are on the defensive, narrowly focusing on agreeing union recognition and consolidating their power base, rather than working directly with employees in the workplace to fight for issues that matter to them.

But there’s a way to turn the tide on decades of decline and reinvigorate unions as vehicles for change in the workplace and the wider community. In the US this has taken the form of “bargaining for the common good”, where unions use strike action to lift up community concerns outside the workplace, going far beyond the traditional demands of wages, benefits and job security.

The Chicago Teachers Union (CTU) coordinated strike action with the union representing school support staff. It also formed alliances with groups outside the workplace, such as with Black Lives Matter, in a shared recognition that “education justice is racial justice”. In a school district where nearly half of students are Latinx and nearly one in five don’t have English as a first language, the CTU demanded new guarantees for bilingual education. It called for more dedicated teachers for English language learners, and a declaration that Chicago schools are sanctuary spaces for students who are immigrants, Muslims or LGBTQI+. The union also demanded reduced class sizes, as well as a nurse, counsellor, librarian and social worker in every school. Most ambitiously, it demanded an expansion of affordable housing for educators, students and parents.

Coordinated action led to 30,000 workers going on strike for 11 days, impacting more than 300,000 students. The strike had enormous public support and piled pressure on the city’s mayor, Lori Lightfoot, who was elected on a progressive platform. Although the city did not meet all their demands, it agreed to spend millions of dollars on reducing class sizes, hiring hundreds more social workers, nurses and librarians, and increasing school staff salaries by 16% over five years.

Unions in the UK can learn from the strategy of the CTU by moving towards a form of unionism which focuses on organising workers from the ground up, as well as aligning work-based organising with broader campaigns. Larger unions could look to actively organising social care workers to fight for better pay and conditions, as well as lower staff-to-patient ratios. In this way, unions could unify the interests of workers, people receiving care and the public, fighting for a social care system that treats its workers well and provides quality care and dignity later on in life. Even more ambitiously, care workers could align their interests with the hundreds of thousands of climate strikers to recognise that a sustainable economy will be built on low-carbon jobs like care work.

It’s not too late to halt the decline of trade unions. “Social movement unionism” could form the basis of a new model of organising, expanding beyond the workplace and integrating other struggles and movements, as part of a broader attempt to rebalance power in the economy.

Historically, unions have been the most important progressive force ensuring we have a society and an economy that works for the majority of people. Union wins are things we take for granted today, including the two-day weekend, paid annual leave, paid parental leave, equal pay rights, and much else besides. New Economics Foundation (NEF) research has also shown that unions are an essential part of a well-functioning economy through bargaining for higher wages, which in turn drives national income more than growing company profits. Trade unions are vital to a good economy, so it’s important to make them as effective as possible.

In an economy that is failing the majority of people, we need trade unions who are willing to look beyond their base and engage with wider societal struggles.

• Aidan Harper is a researcher at the New Economics Foundation