Pret A Manger has launched its first full-ingredient labelling trial at a store in Victoria, London.

The UK-based sandwich chain is taking steps to avoid further allergic reactions following the deaths of Natasha Ednan-Laperouse, 15, and Celia Marsh, 42, who both died after consuming Pret products.

Ednan-Laperouse suffered a fatal heart attack on board a flight in 2016 after consuming a Pret baguette containing sesame seeds, to which she was allergic. Marsh died last year after consuming a Pret dairy-free flatbread that contained traces of dairy.

Pret claimed that the flatbread’s supplier was responsible for the contamination.

Pret CEO Clive Schlee said in a statement: “After an enormous amount of work from a dedicated Pret team, I’m pleased to say that we have launched the first full-ingredient labelling pilot in a shop in Victoria this week. It’s the latest in a series of changes we’ve been making to Pret’s allergy policies since we first learned of Natasha’s tragic death in the spring of 2017.

“I know that sticking labels on sandwich boxes may seem simple, and you may be wondering why we don’t just get on with it. The reason is that we have to make sure the process is safe, practical and effective. The wrong label on the wrong sandwich can be worse than no label at all. Our teams make our sandwiches and salads in small batches, typically around 12 to 15 at a time, throughout the day in over 350 different Pret kitchens all over the country. We have to perfect the process to minimise the chance of human error.”

The chain will enhance the ingredients labels, ensure they are placed in an appropriate place on packaging and look to technology solutions for assistance before rolling out this approach nationwide.

Schlee said: “Speed is of the essence, but so is developing a process that is safe to use. Running pilots now will make the national launch much quicker and easier. We’ll be sharing the learnings with the government and wider industry.”