What is a city but its people? That question was asked on Manchester international festival’s opening night at a living installation in Piccadilly Gardens where local people paraded on a catwalk, offering up their stories. As the festival heads towards its climax, the question is raised again in Cotton Panic!, a piece of gig-theatre created by Jane Horrocks, her partner Nick Vivian and the band Wrangler.
The show uses music, projections, video and clog dancing to contemplate what today’s globalised world in crisis might learn from the cotton famine in Lancashire in the early 1860s, which was a consequence of the American civil war. In 1860, America exported a billion pounds of cotton to Lancashire. But when anti-slavery Union forces established a blockade of Confederate ports, it damaged the cotton exports upon which the southern states’ economy relied. Lancashire’s looms soon fell silent and its people went hungry. Their response? In 1862, they gathered at Manchester’s Free Trade Hall to express their solidarity with those attempting to end slavery in the American south.One of the pleasures of a festival is the way different pieces of work bounce off each other in unexpected ways. As Horrocks’ extraordinary voice soars through the damaged roof of this Victorian market it seems to work in harmony with Theatre-Rites’ marvellous MIF show The Welcoming Party, about how we treat refugees and each other. It floats, too, over Thomas Ostermeier’s production of Returning to Reims, which raises questions about the role of the individual in bringing about political change.

Cotton Panic! tells us how Manchester grew from a population of 94,000 in 1801 to 460,000 in 1861, with the city becoming known as Cottonopolis. But what was this industry built on? The labour of black slaves in the US and mill workers who, in the good times, may have had the highest average wage in the UK but were also among the worst educated. As the looms screech like an express train, and cotton falls like snow on the three large screens around the market space, Horrocks sings: “This is a mill town,” and then counters it with “the town is a mill”. The people were mere cogs in the machine. By the time Marx wrote about the connection between the exploitation of black slaves and “wage slavery”, the people of Lancashire had worked it out for themselves. In Cotton Panic! the names of the mill towns of Lancashire are called out side by side with the cotton-producing towns of the southern states.
Musically, this 70-minute piece, delivered to a standing audience, is a pleasure as the folk songs of the Lancashire workers meld with the gospel tunes of the slaves. Theatrically, it is a bit thin: there are too many images of Horrocks floating ethereally through blizzards of cotton, and not enough of visual interest. The tone is often a mite earnest, as if this is a well-meaning history lesson with added music.

Glenda Jackson pops up on screen to deliver the poet Edwin Waugh’s account of the terrible suffering of laid-off mill workers and their families. Towards the end there is a collage of images of Theresa May, Donald Trump and Black Lives Matter protests, as if pressing us to make connections we will have already made. Just as the starving mill workers of mid-19th century Lancashire recognised that their struggles were intimately linked with those of people living thousands of miles away.
• At Upper Campfield Market Hall, Manchester, until 15 July. Box office: 0843-208 1840.