The arrest of Damian Green last Thursday, his subsequent detention and interrogation, together with the police search of his home and his office in the Palace of Westminster, constitute the most serious breach of the privilege of Parliament in modern times. At least eight senior figures in the British Establishment were involved; they either initiated the action, agreed to it, conducted it, or allowed it to continue. Not one of them seems to have understood how serious a “high crime or misdemeanour” they were conspiring to commit. The police may have thought that they were legitimately investigating a crime; in fact, they were committing one, a much more serious crime than the one they imagined they were investigating. The House of Commons remains the centre of our democracy. The freedom of Britain cannot survive if the centre does not hold.