A paragon of the kind of people-powered progress that feels all the more necessary in divisive times, the Living Wage campaign, is celebrating its25th anniversary this year.

Born out of Telco (The East London Citizens’ Organisation), which ultimately became the nationwide group Citizens UK, the campaign has always involved communities working together, to press for social and economic change.

A quarter of a century on from its foundation among the churches, mosques and community groups of east London, it has just signed up its latest living wage employer, the Department for Business and Trade.

It is a particularly symbolic victory, because one of the campaign’s more high-profile actions over the years, back in 2012, involved contracted-out cleaners placing letters on the desks of senior ministers, outlining the low pay rates they were forced to survive on, while keeping Whitehall’s maze of offices spick and span.

More than a decade on, staff including cleaners and security guards at the department will now be paid a minimum of the London living wage of £14.80 an hour, in a move celebrated by business minister Kate Dearden, a staunch trade unionist, as “giving working people the backing they deserve”.

Methodist minister Paul Regan and senior NHS leader and Catholic activist Bernie Harris, who were both involved from the earliest days, reminisced last week about the campaign’s challenges and triumphs.

Driven by the late Neil Jameson, a vigorous and determined organiser, they built a coalition of religious groups, community organisations and concerned local citizens.

“I’d always worked in the health service. And I was always conscious of families with not enough money to live on,” Harris recalls. “And I was also very conscious that poverty and ill health were so linked.”

Regan explains: “We did a sort of listening campaign around the 30 or 40 member institutions in Telco. The basic issue that we were seeing our families confronting was low wages – people having to work several jobs to make ends meet – and the cost of housing. Those were the two major pressing issues.”

The campaign got expert economists to calculate what wage rate it would take to make ends meet as a family and found that it far exceeded the then statutory minimum. “Living wage” was not a new term, but this powerful idea became the centrepiece of Citizen UK’s organising.

These days, the real living wage is calculated each year by the Resolution Foundation thinktank. This year’s rate outside London is £13.45.

The personal experiences of those at the sharp end were always an important negotiating tool. The group bought shares in HSBC, so that a cleaner who worked in its glass and steel Canary Wharf headquarters, Abdul Durrant, could attend the bank’s annual general meeting in 2003 and confront its then chair, Sir John Bond, with his personal experience of poverty pay – then £5 an hour.

In those pre-financial crisis days when the City’s economic power was all but unchallenged, it seemed outlandish that a ragtag band of faith leaders and grassroots activists could shame the global financial giant into action. But they received a 28% pay rise the following year; and HSBC later signed up as a living wage employer.

“On every occasion, when the negotiation was taking place, it would be the cleaners who would take the lead,” says Regan. “We would identify and support and train somebody who was willing to be a spokesperson on behalf of the other low-paid people. But they would be surrounded in the room by vicars, and nuns, and various people, who would be there as back stoppers.”

Harris says the secret of the organisation’s success has always been “relational power” – working out who the decision-makers are, and developing a personal connection with them.

In her local patch of Redbridge, east London, she cites Wes Streeting and Iain Duncan Smith as early and consistent supporters.

Citizens UK took to holding lively and high-profile assemblies ahead of London mayoral elections, and then before general elections, to challenge the candidates on members’ priorities, including pay.

Over time, so prominent did the idea become, that in a backhanded compliment, George Osborne rebranded the statutory minimum wage in 2015 as the “national living wage”, committing to lift it over time to two-thirds of the UK median – an extraordinary political shift from a party that had opposed the introduction of the minimum wage.

Citizens UK responded by insisting that its own, higher, voluntary rate remained the “real living wage’”, and pressed on with signing up willing employers.

Many of the challenges to a decent life identified in those early community meetings, have moved from the fringes to the heart of political debate in the intervening decades, as the UK economy has been rocked by a series of shocks, from the 2008 crash to the ongoing Iran war.

The shape of the wage distribution has been shifted dramatically by the upward march of Osborne’s national living wage, helping to reduce hourly wage inequality – and prompting even the Resolution Foundation to urge caution in future uprating.

Some of the other issues Citizens UK has long highlighted, including the precariousness of work and the unpredictability of hours, are scheduled to be tackled by Labour’s Employment Rights Act.

Still based in east London, Citizens UK has been turning its attention more recently to the paucity of pensions provision for many low-paid workers – while continuing to put pressure on stingy employers.

Still campaigning hard after all these years, Regan says he now has the supermarket sector in his sights; while Harris is working hard on penny-pinching private care providers. All power to their elbows.