His selection by Conservative Home Secretary Michael Howard was regarded as a bid to avoid criticism of the struggling jail system by putting an establishment `patsy' at the helm of the inspectorate.
The former Adjutant-General, who had been given the Army nickname of Rambo, was expected to exude a disciplinarian no-nonsense attitude that would have little time for the agenda of penal reformers.
But within days of taking the job in 1995, Sir David showed that he was just as much his own man as his predecessor, Sir Stephen Tumim, a former judge who had never shirked from exposing the failings of prison bosses.
Sir David's gesture of leading his team out of Holloway women's prison in London in protest at the squalid conditions inside the jail set the tone for his style as Chief Inspector.
Since then he has drawn up an agenda for improving conditions that has been espoused in a long series of critical reports on failing prisons.
His favourite issues are reducing drug problems and jail suicides, improving conditions for women inmates and young offenders and concentrating prisons of differing security level in convenient clusters.
Sir David, 64, first drew attention to the problems at Wormwood Scrubs in west London in 1997 and reacted furiously when no improvements were made by the time he returned this year. He recommended that the Prison Service considered privatising or closing the prison.
But some of Sir David's criticisms have rankled ministers and prison managers who feel they are unjustified.
In July, Home Office minister George Howarth went before the Home Affairs Select Committee to say that the Chief Inspector's views were not always supported by evidence. He accused the Chief Inspector of misleading MPs.
But as a Falklands War veteran and survivor of an IRA assassination attempt, Sir David is unlikely to succumb to any intimidation.Reuse content