Pret a Manger says it sources the chicken from Brazil because the animal welfare standards at the factory it uses are higher than at British rivals and also because Brazil is able to supply the volume it needs. The meat is frozen and shipped to the UK, where it is prepared for Pret's sandwiches.
The Sunday Telegraph highlighted the fact that Pret's packaging says the sandwiches contain "the best, natural stuff you'd want to use at home" and "just made with preservative-free, fresh, natural ingredients" as part of its campaign to simplify food labelling.
Last week the newspaper tackled the company over the sourcing of fish for its sushi, which is shipped from Chile.
In both instances, Pret a Manger has changed details on its website, following publication of the story. In the case of the chicken, Pret a Manger has told the newspaper that it is unhappy about sourcing from Brazil and that the policy would change.