He is the author of many books and articles on criminal justice and penal policy and was co-editor (with Mike Maguire and Robert Reiner) of the influential 'Oxford Handbook of Criminology' (5th Ed, 2012, Oxford University Press).
He frequently acts as an expert witness in extradition proceedings in which there is a possible breach of Article 3 of the European Convention for the Protection of Fundamental Human Rights, which forbids torture or inhuman or degrading treatment or punishment.
He was an Assessor to Lord Justice Woolf's Inquiry into the 1990 prison disturbances, was until 2011 a Ministry of Justice-appointed advisor to the criminal justice inspectorates for England and Wales and has most recently been a member of the Daniel Morgan Independent Panel (a Government inquiry into Daniel Morgan's murder in 1987).
He demonstrated his conspicuous independence by questioning, mostly behind the scenes but occasionally in public, the wisdom of the Government's anti-social behaviour policy as it impacted youth.
He also made it clear that he considered his role to include representing to Government the front-line operational experience of youth offending team (YOT) practitioners and argued that the YJB should adopt a less directive and a more supportive stance than hitherto.
He argued that the strength of the reformed youth justice system lay in the YOTs being devolved, multi-agency, locally accountable agencies.
He argued for and introduced the joint inspection of youth offending teams (YOTs), arrangements which were to be led by HM Inspectorate of Probation.
In his annual reports he expressed doubts about placing too much reliance on cognitive behavioural programmes for offenders and argued against the 'sentencing drift' which he maintained was serving to 'silt up' probation caseloads.
: Police Community Consultation Arrangements in England and Wales, Centre for the Analysis of Social Policy, University of Bath.
1989 The Perrie Lectures 1988, Remands in Custody: problems and prospects, London: Home Office, Prison Department 1989 (with C.Kemp) Behind the Front Counter: Lay Visitors to Police Stations, Bath/Bristol Centre for Criminal Justice Papers No 1.
1990 (with C.Kemp) Lay Visitors to Police Stations: Report to the Home Office, Bristol Centre for Criminal Justice.
Policing and Crime Prevention: Papers from the British Criminology Conference 1989, Bristol Centre for Criminal Justice.
1993 (with M.Barker) Sex Offenders: A Framework for the Evaluation of Community-Based Treatment, London: Home Office Research and Planning Unit.
1998 (with Hoyle, Cape and Sanders) Evaluation of the 'One Stop Shop' and Victim Statement Pilot Projects, Home Office, Research Development and Statistics Directorate.
1999 (with Davis, Hoyano, Keenan and Maitland) An Assessment of the Admissibility and Sufficiency of Evidence in Child Abuse Prosecutions, London: Home Office.
2004 Report of an Inquiry into the Death of PC Gerald Walker at the hands of Mr David Parfitt, HM Inspectorate of Probation, London: HMIP.
2021 with O'Loan (Chair), Casale and Kellet 'The Independent Daniel Morgan Panel Report' 3 Vols, HC, Current Work Together with Stephen Shute of the University of Sussex he holds a British Academy award to undertake research on 'Inspection and Accountability of Criminal Justice Services' on which a book is planned to be published by OUP.