Brands can’t choose their customers. So what happens when extremists wear their clothes?

London
 — 

When right-wing protestors took to the streets of London in September, the turnout was one of the largest in decades. More than 110,000 people showed up to rally against immigration, many carrying flags of England and Britain as they scuffled with police. But alongside the Union Jack and St George’s Cross, another symbol was unexpectedly visible: the logo belonging to the Italian fashion brand Stone Island.

A nautical star and compass overlaid on a button-on cloth badge with green, yellow and black detailing, the design frequently appears on Stone Island’s clothes — and during the protest, they were worn by Stephen Yaxley-Lennon, the far-right anti-Islam activist and English Defence…