40.45Investigative select committees examine issues of public importance within their orders of reference and make reports on the basis of the evidence received. The main investigative committees are the European Union Committee, the Science and Technology Committee, the Economic Affairs Committee, the Communications Committee, the Joint Committee on the National Security Strategy, and the International Relations Committee. The Constitution Committee and the Joint Committee on Human Rights undertake both legislative and investigative work. The Secondary Legislation Scrutiny Committee may also conduct broad inquiries from time to time.

From 1993 it became usual for at least one additional ad hoc committee to be appointed each session on a subject of general interest. Since 2014 four ad hoc committees have been appointed each session, including at least one appointed to conduct post-legislative scrutiny.1


  1. 1. Liaison Committee, First Report of Session 2013–14, HL 145; LJ (2013–14) 1654. In Session 2012–13, three ad hoc committees were appointed. In Session 2013–14, three ad hoc committees were appointed for the full session, and two short ad hoc committees were appointed on a trial basis, one lasting around six months, followed by another lasting around five months. The trial was not repeated. In Session 2017–19, four ad hoc committees were appointed with orders to report by 31 March 2018 (Minutes of Proceedings, 29 June 2017) and a second tranche of four ad hoc committees were appointed for the remainder of that session (Minutes of Proceedings, 9 May 2018).