Pret a Manger is to begin a national rollout of full lists of ingredients on freshly-made products from Thursday to fulfil a pledge to improve labelling after the deaths of two customers who suffered allergic reactions to its sandwiches.

A five-point plan being unveiled by the chain will also include the launch of tablet computers in every shop, containing detailed information about ingredients, and a commitment to bolster transparency by publishing quarterly food safety reports.

The new labels have gone live in 20 London stores this week, with further rollouts to its remaining 380 UK outlets planned for later this month and over the summer.

The company is investing millions of pounds on label printers for every outlet and training thousands of workers as it revamps its systems amid a government consultation on tougher allergen labelling.

There has been widespread concern about the issue since 15-year-old Natasha Ednan-Laperouse died in July 2016 after eating a Pret a Manger baguette containing sesame seeds, to which she was severely allergic. The item did not have any allergen advice on its wrapper and there was no legal requirement for it to do so.

The coroner investigating her death last year criticised Pret’s labelling and the whole UK system as “highly inadequate”.

The second fatality involved Celia Marsh, 42, who died on 27 December 2017 after eating a vegetable flatbread containing a yoghurt that was supposed to be free of any milk products but was found to be contaminated with dairy.

“The issues of allergies has struck a deep chord within Pret a Manger following the tragic deaths of Natasha Ednan-Laperouse and Celia Marsh,” said Clive Schlee, chief executive of Pret a Manger.

“We said we would learn from the past and make meaningful changes. This plan brings together some of the most important changes we have been making to help customers with allergies.”

The first stage of implementation of the new plan follows the completion of a pilot in two shops in Victoria in London, where staff have labelled more than half a million sandwiches, baguettes and wraps since November 2018.

Customers will be able to search through Pret’s menu using the new tablets – which will be rolled out during the rest of the year – to find products they can eat based on their own dietary needs.

The chain will also remove allergens from products which it said would not compromise quality or taste, reformulating more than 70 Pret recipes to remove one or more allergens.

It will also produce detailed updates on food safety and ingredients on a quarterly basis. Finally, it will beef up training and invest an additional £1m in higher rates of pay for those who take on extra training in the new labelling process.

Natasha’s parents welcomed the move. They are urging other major food retailers to follow suit and for the government to enshrine the policy in law.

Tanya and Nadim Ednan-Laperouse said: “We believe the time has come for full information and transparency about what is in our food, as proposed by the environment secretary, Michael Gove, during the current consultation on ‘Natasha’s Law’.

“We hope the entire industry steps up to the mark and supports our call for full ingredient and allergen labelling in pre-packaged food, because no family should ever have to suffer the pain, anguish and dreadful death of a child as we did.’’