A DIMINUITIVE woman in a sari and buttoned-up cardigan stands with her right arm aloft in triumph, as a long line of police holds back crowds of people lining a terraced street. This eye-catching photo (below) captures Jayaben Desai, a strike leader, being cheered by thousands of supporters during the strike at the Grunwick Film Processing Laboratory in Dollis Hill, northwest London that began in August 1976.

Workers, mainly Indian women and men, walked out in protest at exploitative and demeaning treatment such as being coerced into working overtime and having to ask to use the toilet, and sought to form a union. Desai led the strike. Her photo takes pride of place in “We Are The Lions”, an exhibition commemorating the dispute’s 40th anniversary at The Library in Willesden Green, half a mile from where the strike unfolded. The title comes from an altercation between Desai and her boss, who said he was not running “a zoo”. She replied: “What you are running here is not a factory, it is a zoo. In a zoo there are many types of animal. Some are monkeys who dance to your tune; others are lions who can bite your head off. We are the lions, Mr Manager.”

The exhibition details the stories of Desai and the strikers, mostly Gujarati Indians who came as British citizens in the early 1970s from East Africa. Through photos, newspaper articles maps, ephemera such as clocking in and out cards, original strike banners, news footage and pamphlets, “We Are The Lions” brings the dispute, and its tumultuous 1970s context, to life.

Grunwick was a major event in postwar Britain: at the dispute’s peak in June 1977 the “strikers in saris”, as the press called them, drew 20,000 people to Chapter Road and the surrounding streets. Crucially, the union movement got behind the Grunwick strikers, the first time Britain’s existing unions actively supported a dispute involving Commonwealth migrants. Up to that point, unions had regarded labour from British dominions as a threat, as Sujata Aurora of Grunwick 40, the organisers, explains. “Before Grunwick there were immigrant worker struggles, such as Mansfield Hosiery in 1972 and Imperial Typewriters in Leicester in 1974, that were completely ignored by trade unions. Grunwick was the moment immigrant workers became part of Britain’s working class and the labour movement.”

The strikers were backed by 154 unions, as well as cabinet ministers Shirley Williams, Fred Mulley and Dennis Howell, who joined the picket line. As the Union of Postal Workers boycotted deliveries to Grunwick, and picketers clashed with police, the dispute was debated in Parliament and the Labour prime minister, Jim Callaghan, appointed Lord Scarman, a senior judge, to lead an inquiry. He recommended Grunwick reinstate the sacked strikers and recognise workers’ right to a union.

These recommendations were completely ignored, however, and after 23 months the strike failed. It was in race relations that Grunwick’s unity represented a resounding victory. Xenophobic and racist rhetoric was rampant in mid-1970s Britain: in Leicester’s local elections of May 1976 the National Front polled 20% of the vote, and less than a month later Gurdip Singh Chaggar, an 18-year-old Sikh student, was stabbed to death in a racist attack in Southall. Against this febrile backdrop, “We Are the Lions” explains, 20,000 people from across Britain’s races, creeds and classes standing together with a small band of striking Indian women, spoke volumes.

The exhibition connects Grunwick with today’s workers in low-paid, precarious employment—who also tend to be recent migrants. Deliveroo couriers in August successfully protested against changes to their terms that amounted to a big pay cut. The Justice for Cleaners movement at the University of London has called for the same sick leave, holiday and pension benefits as the university’s direct employees. “Younger generations barely know what a trade union is, yet work is more precarious, so we’re looking to see what lessons we can take from this epic struggle in the labour movement,” says Ms Aurora.

“We Are The Lions” also celebrates how a generation of South Asian women who, barely acknowledged, helped reshape Britannia. Women like Desai, having brought a big employer to a halt, were walking refutations of the stereotype of South Asian women as submissive and downtrodden. In 1976, her fellow striker Laxmiben Patel was a mother in her early thirties, working at Grunwick dispatching processed photos. She and her brother, who also worked at at the factory, joined the walkout and were part of the small group picketing in the months before the unions got involved.

Today, in the same house she lived in 40 years ago, Mrs Patel points to the garden where she, her brother and fellow strikers made banners. She recalls that it took time for the walkout to gather momentum, as many of the workers were new to Britain and didn’t know their rights. “I’d joined a union in my last job and had seen they help you. So we explained to our colleagues why we were striking, and some joined the strike. Some didn’t because they couldn’t afford to, but we stayed on the picket line to fight for the rights of all of us.”

Mrs Patel is full of admiration for Desai, who died in 2010 aged 77, for galvanising the walkout, and her tenacity in the face of heavy-handed policing and government pressure to break the strike. “It’s because of Jaya Massi ['Aunty', meaning Desai] that we fight. She was a fighter. Sometimes there were more police than strikers and she would stand with all the police around her with the loudhailer. She was not scared.” Mrs Patel hopes initiatives such as Grunwick 40 can inspire people today. Forty years on, the roar of Grunwick’s lions resonates as proudly as ever.

We Are The Lions is at the Brent Museum & Archives, Willesden Library, London until March 27th