According to Britain's Daily Mail newspaper, citing a CNN study, chicken nuggets sold in U.S. branches of McDonald's contain a chemical used in the children's play item, Silly Putty.

CNN reports that "McNuggets" sold to American fast food lovers contain di-methyl-poly-siloxane, an anti-foaming agent used in Silly Putty. They also have more calories and fat than those sold in the chain's British restaurants.

A spokeswoman for McDonald's puts the transatlantic differences down to local methods of food preparation. CNN reports that U.S. McNuggets also contain a petrol-based chemical called tertiary butylhydroquinone.

British McNuggets contain neither. Lisa McComb, McDonald's global media relations manager, says dimethylpolysiloxane is used for safety reasons to prevent oil from foaming.