Britain's prime minister has issued an apology after comparing heckling from a senior lawmaker to "having someone with Tourette's sitting opposite you."

David Cameron made the comment about Ed Balls, the opposition's shadow chancellor, in an interview in a British newspaper The Sunday Telegraph.

Balls' gestures and comments have become a fixture of the prime minister's weekly grilling in the House of Commons.

Downing Street officials said Cameron's remarks were made "off the cuff."  A spokesman said the prime minister apologizes if anyone was offended by his comments.

Tourette's syndrome is a neurological disorder characterized by recurrent involuntary movements, and sometimes vocal tics, including grunts, barks or words, especially obscenities.