MONTREAL — The friends from Quebec went to London’s Brick Lane food market, searching for a taste of home. But as they devoured their poutine — that gloppy, trouser-bursting dish of French fries, cheddar cheese curds and gravy — something felt horribly wrong.

The dish tasted just right — so authentic that the cheese curds emitted a faint “squeak, squeak” when bitten into — the telltale sign of a proper poutine.

But the jovial chef serving them had an Ontario accent. Even more disconcerting: He was wearing the hat of the Toronto Maple Leafs hockey team, the archrivals of the Montreal Canadiens.

“Poutine is Quebecois; it is not Canadian,” said Zak Rosentzveig, 25, a poutine-obsessed economist from Montreal, recently describing his visit to the food stall and adding his voice to a simmering debate over poutine’s true identity.