Centre stage at Disobedient Objects, an exhibition at the V&A, London that aims to explore the connection between social protest and art, will be a banner designed in 2013 by Ed Hall for the South Yorkshire branch of Unite. Emblazoned with the words "Still the Enemy Within" – a reference to the expression used by Margaret Thatcher to describe the striking miners – the banner, in traditional crimson and gold, was stitched in the south London garage that doubles as Hall's workshop, and took him about 150 hours.
Hall is Britain's leading designer of marching banners for trade unions and other campaign groups, an odd sort of career into which he stumbled more than 30 years ago (by training, he is an architect). But Hall is also, thanks to an ongoing collaboration with Jeremy Deller, the Turner prize-winning artist who represented Britain at the 2013 Venice Biennale, fairly used to seeing his work in galleries.
"Basel, Venice, Paris… Jeremy has given me some of the most amazing experiences of my life," he says. "I made 50 banners for his exhibition [From One Revolution to Another, 2008] at the Palais de Tokyo in Paris. Just to wander through that city knowing I'd work to do there! It was wonderful."
Deller discovered Hall a decade ago at the Lambeth country show in Brockwell Park, south London; the banner that caught his eye – it eventually appeared in Deller's show Folk Archive – commemorated the Brixton bomb of 1999 and an anti-racist march that followed it. In the years since, Hall has made him many hundreds more. "They've become a bit of a motif in my work," Deller says. "Though it must be boring for Ed because I often ask for very simple text banners." Hall nods. "That's true. For Venice, I was hoping to get the Salute and the Lagoon. But there was none of that, sadly."
Hand-sewn union banners are unique to these islands, perhaps because – this is Hall's theory – in Catholic Europe, people put their efforts into stitching for saints' days: "When the trade unions came along, they adopted the pictorial imagery of the Bible – rising suns and so on – without having to worry about the church." His favourite banners, though, are those made by the suffragettes in their own ateliers. Does he feel he must work within the traditions, or is he keen to suggest new iconography?
"Not really. Most of the groups that commission me want dignity and gravitas in their banners, and that's what I'm interested in too. I don't think you could successfully make a jokey banner." Has he ever made one for a right-wing group? "Well, the Countryside Alliance have never asked. But I wouldn't make one that, say, promoted grammar schools. Then again, I wouldn't make a Stalinist banner either."
Come and hear Jeremy Deller speak at the Observer Ideas festival
Given the history of the past 25 years, in which union power has grown ever more limited, it is perhaps surprising to hear how busy Hall is. "The order book is always just at the point of panic. I've got eight to do at the moment, including one for Newcastle RMT which will have the Tyne and its bridges in it." So Deller must wait in line? They laugh, but no answer is forthcoming. My hunch is that very occasionally and somewhat undemocratically, the famous artist gets to jump the queue.
Disobedient Objects is at the V&A, London SW7 from Saturday until 26 February. Jeremy Deller will be appearing at Observer Ideas at the Barbican, London, a day-long festival of talks and performances – click here to book tickets