These Rules amend the Prison Rules 1999 (S.I. 1999/728) (“the 1999 Rules”) and the Young Offender Institution Rules 2000 (S.I. 2000/3371) (“the 2000 Rules”). These Rules specify substances or products which are “specified drugs” for the purposes of section 16A (testing prisoners for drugs) of the Prison Act 1952 (c. 52) (“the Act”). The effect of section 16A of the Act is that a prison officer can require a prisoner or an inmate to provide a sample for the purposes of ascertaining whether there is a specified drug in the body of the prisoner or inmate. The effect of the amendments to rules 2 and 50 (compulsory testing for controlled drugs) of the 1999 Rules and rules 2 and 53 (compulsory testing for controlled drugs) of the 2000 Rules is to list the specified drugs and provide for compulsory testing of those specified drugs.