The not-so-Happy Meal was reportedly served Tuesday at a McDonald's in a London suburb. Laura Arber, the upset mother, claims her 6-year-old daughter, Maddie, started making choking noises after chowing down on the McNuggets.

Laura claims she put a finger down her daughter's throat to make her throw up the food, which she says was speckled with blue. Mom says she did some more investigating, puzzled by what her daughter was eating, tearing into the Chicken McNuggets with her fingers to discover parts of a blue surgical face mask.

Laura posted video showing what appears to be more blue face mask parts inside other Chicken McNuggets her daughter had not yet eaten ... and it's really gross.

McDonald's corporate office has since apologized for the incident ... and mom says her little girl is fine.