The company said that, by next month, all foods will also be 100 per cent aspartame-free. M&S has banned additives associated with concerns about food intolerance and children's diets - including artificial colourings such as ponceau 4R, sunset yellow, carmosine and quinoline yellow, which are used in cakes and bakery.
The retailer also said that it is looking at ways to remove artificial colourings and flavourings from the most challenging area: confectionery.
M&S director of technology David Gregory said: 'At the heart of our Plan A announcement earlier this year was our commitment to help customers lead a healthier lifestyle.'
The move has been welcomed by charity the Hyperactive Children's Support Group (HACSG), which recommends the removal of artificial additives from foods. HACSG project director Nick Giovannelli said: 'We welcome the effort by Marks & Spencer. This is a significant undertaking and a big commitment - one that we believe consumers will welcome.'
Yesterday, Asda pledged to remove artificial colourings and flavourings from all its own-brand products by the end of the year. The grocer also said it will invest more than£30 million in reformulating products to ensure that taste is not affected.