How did a ‘vegan’ flatbread in Pret a Manger come to contain milk protein?

The flatbread form Pret a Manger included a coconut milk yoghurt, made in England, that contained traces of milk protein. Photograph: Neil Hall/Reuters

Celia Marsh, 42, a dental nurse and mother of five from Melksham, Wiltshire, who had a severe allergy to cow’s milk, collapsed and died in December 2017 after eating a Pret a Manger “super-veg rainbow flatbread” found to contain traces of milk protein. We explain how the “vegan” flatbread bought in Bath was “contaminated” with a coconut milk yoghurt developed in Australia and made in England – with a “secret” ingredient manufactured in Wales.

• In 2011, former police officers Bethany and Paul Eaton spotted a demand for tasty dairy-free products that were not soya based. They contacted an Australian company called CoYo that produced a dairy-free yoghurt using coconut milk.