Former chief constable Sir Ronnie Flanagan has been appointed Her Majesty's Chief Inspector of Constabulary.
Sir Ronnie's new appointment is effective immediately
The job, with a salary of £189,000, involves inspecting police forces in England and Wales, as well as the PSNI.
He stood down as Northern Ireland chief constable in 2001, after five years in the post.
The announcement of the appointment was made by Home Secretary Charles Clarke on Tuesday.
Sir Ronnie will succeed Sir Keith Povey as head of the organisation.
The 55-year-old has been one of Her Majesty's inspectors since 2002 after heading the RUC, and later the PSNI, from 1996 to 2001.
Mr Clarke said: "Sir Ronnie has a proven record of operational and managerial achievement at the highest levels of the police service.
"His long involvement in policing - both as an officer and as an Inspector of Constabulary - means he is well placed to advise ministers, the Home Office and other tripartite partners on policing issues."
The new appointment, expected to be for three years, is effective immediately.
In 2002, Sir Ronnie become the only person from Northern Ireland ever to receive a Knight Grand Cross of the Order of the British Empire (GBE).
He was honoured for managing the changeover from the Royal Ulster Constabulary to the Police Service of Northern Ireland.
In 2003, Sir Ronnie Flanagan was appointed to head a review by Her Majesty's Inspectorate of Constabulary into how Cambridgeshire Police conducted the early stages of the Soham murder inquiry.