See catalog of the latter collection by G. Reynolds (1960); C. R. Leslie, Memoirs of the Life of John Constable (enl. ed. 1937); collections of his letters by P. Holmes (1931) and R. B. Beckett (1962); biography by B. Taylor (1973); studies by C. Peacock (rev. ed. 1972) and R. Gadney (1976).
He presided over an external police inquiry into allegations in Northern Ireland of collusion between the British Army, the Royal Ulster Constabulary and loyalist terrorists in the murders of Irish nationalists. Stevens's third report, published on 17 April 2003, upheld the claim and explicitly said that collusion leading to the murder of nationalists (and some unionists wrongly thought to be Catholic or nationalist) had taken place. In the aftermath of his shock report, David Trimble, the leader of the Ulster Unionist Party, called for a parliamentary inquiry into the collusion, while the leaders of the Social Democratic and Labour Party and Sinn Féin called for a full public inquiry.
Lord Stevens is the Executive Chairman of Quest Ltd, a London based Corporate Intelligence, Investigations and Risk Mitigation Company. Among at least four remunerated company directorships held by him are non-executive directorships of the financial services company Invicta Capital and of Mercer Street Consulting. Stevens also writes for the News of the World newspaper. On 28 November 2005 he was appointed Chancellor of Northumbria University.
As a result of the 2006 allegations of corruption in English football by various media sources, Lord Stevens was asked by the Football Association to head up the inquiry in liaison with Quest Ltd On 2 October 2006, it was announced by the Football Association that Lord Stevens' inquiry had been extended by two months to investigate 39 transfers involving eight clubs. On 20 December 2006, Stevens presented his preliminary report, which found that the level of corruption within English football was not a high as had been anticipated, there were several causes for concern. 17 transfer deals were still subject to further scrutiny.
On 15 June 2007, Lord Stevens' inquiry issued its final report which raised concerns over issues involving 17 player transfers, involving five clubs, three managers and numerous agents and other third parties. In summary, the report stated: “there is no evidence of any irregular payments to club officials or players, and they are identified only as a consequence of the outstanding issues the inquiry has with the agents involved”.. For further details of the inquiry findings see Stevens report.
Lord Stevens holds a Commercial Pilot's Licence and part owns a Cessna light aircraft.