PRET a Manger will list all ingredients, including allergens, on its freshly made products following the death of a teenager who had an allergic reaction after eating a Pret sandwich.
Natasha Ednan-Laperouse, 15, went into cardiac arrest on a flight after buying a sandwich at Heathrow Airport in 2016.
Theresa May called for a review of food labelling laws on Tuesday in the wake of her death.
Clive Schlee, Pret chief executive, said again the firm was “deeply sorry”.
“I said we would learn from this tragedy and ensure meaningful changes happen,” he said.