North Korean diplomats have asked the British government to take action against a London hair salon's poster poking fun at distinctively coiffured leader Kim Jong-un.

Bad hair poster

Bad Hair Day poster in London draws consternation from North Korea. (Twitter)

The Foreign Office said Wednesday it had received a letter from the country's embassy objecting to the poster, and was considering its response.

The Evening Standard newspaper reported the letter urged Britain to take "necessary action to stop the provocation."

Staff at M&M Hair Academy say they were visited by diplomats from the nearby embassy after putting up a poster featuring a picture of Kim — who sports a distinctive undercut — and the slogan "Bad Hair Day?"

Police say they spoke to both parties and determined no crime had been committed.

The embassy didn't immediately respond to a request for comment.