Luke Johnson, former chairman of PizzaExpress and later the man in charge of the restaurant company Signature, has been appointed the surprise new chairman of Channel 4, the television station. Johnson's most famous previous involvement in television is when he stormed off the BBC TV series Back to the Floor, in November 2000, while working as a waiter in one of his own restaurants, telling the crew to "stick your programme". He is also the son of the historian and journalist Paul Johnson, who has been one of Channel 4's fiercest critics over the years and who called Michael Grade, the former Channel 4 chief executive, Britain's "pornographer in chief". However, Johnson, 42, worked early in his career at TV-am and BMP, the ad agency, before becoming a researcher for Jonathan Aitken, the disgraced cabinet minister, and later moved to Kleinwort Benson as a media analyst.