Tag questions are generally regarded as the most conducive (i.e. controlling) type of questions occurring in courtroom examinations. This paper addresses the questions of the specific contributions given by each tag question type to interaction control and to the related phenomena of hostility and aggressiveness. The analysis has been conducted on the hearing transcripts of the Hutton Inquiry, a public independent judicial inquiry set up by the British Prime Minister Tony Blair and carried out by the judge Lord Hutton in 2003 to investigate the death of the government scientist David Kelly.