Functions and powers 2 Functions 10 (1) The Commissioner’s general function is to support and promote the adoption of lawful, effective and ethical practices in relation to the acquisition, retention, use and destruction of biometric data for criminal justice and police purposes by— (a) the Police Service of Scotland, (b) the Scottish Police Authority, 15 (c) the Police Investigations and Review Commissioner. (2) But the Commissioner’s general function does not extend to biometric data in relation to which the Commissioner for the Retention and Use of Biometric Material has a function under section 20 of the Protection of Freedoms Act 2012. (3) In exercising that general function, the Commissioner is to— 20 (a) keep under review the law, policy and practice relating to the acquisition, retention, use and destruction of biometric data by or on behalf of the persons referred to in subsection (1), (b) promote public awareness and understanding of the powers and duties those persons have in relation to the acquisition, retention, use and destruction of 25 biometric data, how those powers and duties are exercised, and how the exercise of those powers and duties can be monitored or challenged, (c) promote, and monitor the impact of, the code of practice.