The retired director of the US Drugs Enforcement Administration has been appointed Oversight Commissioner to monitor the implementation of the Patten report recommendations on policing.
Mr Tom Constantine (60), a former New York State police chief, was described by the Northern Secretary, Mr Peter Mandelson, as having the "know ledge, experience and professionalism needed for the post".
"I think we are very lucky to have him," said Mr Mandelson, who considered a number of applicants. "He has set aside alternative offers since his retirement to assist us in Northern Ireland with the implementation of policing reform. The Prime Minister and I are extremely grateful to him for agreeing to take on this challenging role."
Mr Constantine said: "My job will be to be a very objective finder of facts and if legislation eventually develops out of the process, and there's a decision on the part of elected and appointed officials, that this will be the protocol. My position will be to make sure that that's clearly reported on, adhered to and fulfilled."
People must feel it was their police service and that it was apolitical, developing and providing a service irrespective of religion, colour, political party, or ethnic background, he said. "Where police departments in the United States, which is most of my experience, have faced the most difficulty is when people in those communities do not feel that that's their police department."
Mr Constantine met Mr Mandelson yesterday and will start work immediately. He will stay in Northern Ireland for a few days and is expected to return towards the end of June. He will have progress review meetings approximately every four months with ministers, the RUC Chief Constable, the Police Authority and others.
The British government said the appointment would not cut across the responsibilities of the new Policing Board or the Chief Constable, and the accountability of ministers to Parliament on policing issues would not be diminished.
Mr Constantine is expected to produce a formal report in October, which Mr Mandelson said he hoped would be positive and constructive, "but which could also highlight and comment on delays or failures and I will lay this before parliament and it will be published".
Mr Constantine had a reputation as a no-nonsense cop when he served in the New York State police for 30 years, before being appointed by the Clinton administration to head the DEA, where he served for five years before retiring rather abruptly last July.
Mr Constantine marches in St Patrick's Day parades as an Irish-American with roots in Co Clare. He was born in Buffalo in 1938 and entered the New York state police academy in 1968.
He and his wife, Ruth Ann, have six children.