Gang leader Gerald Matticks controlled the drug trade through Montreal’s port

A few months ago, I went to a birthday party at a bar in Neepsend, an old industrial neighbourhood by the River Don in Sheffield. The bar had been a steelworks once, but now it was another example of the international style you find everywhere, from Portland, Oregon, to all the other Portlands in Canada, England, Australia, and New Zealand: exposed brick, steel beams, concrete floors, Edison bulbs. The steelworkers had been transformed into accountants and brand managers, the molten pig iron into £9 cocktails. When we sat down for dinner, I was placed next to a German who ran a small...