Copied from another site in case anyone buys this - it's not about my child.

"just wanted to let people know that last night my son, who is allergic to peanuts, had the m & s chicken arrabbiata and spaghetti carbonara, both of which he has had before and been ok with, and suffered a reaction. I have rung M&S to let them know that it seems like there may be a cross contamination issue or perhaps they have changed suppliers for some ingredients.
The lady whom I spoke to was very polite and pleasant, however advised me to take the packaging " at my own convenience" back to the store, she didn't really seem to appreciate the severity of the situation."