LONDON, Sept 17 (Reuters) - A lawyer for the British government told the Supreme Court on Tuesday that if it ruled that Prime Minister Boris Johnson's decision to suspend parliament in the run-up to Brexit was unlawful, he would take action to remedy the situation.

"It will be then for the prime minister to address the consequence of that declaration (that the suspension was unlawful)," Richard Keen told the court during a hearing.

"The consequence could be that he goes to the queen and seeks the recall of parliament," he said.

Asked by one of the judges to clarify what sort of action Johnson might take if the court ruled he had acted unlawfully, Keen said: "I have given a clear undertaking that the prime minister will respond by all necessary means to any declaration that the original prorogation was affected by any unlawful advice that he might have given."

Asked whether Johnson could seek a new suspension, Keen said: "I'm not in a position to comment on that proposition." (Reporting by Estelle Shirbon; editing by Stephen Addison)