Lord John Stevens has been given responsibility for two high-profile inquiries - the death of Princess Diana and allegations of British football corruption.
Lord Stevens has a history of leading high-profile inquiries
The results of his eagerly-awaited investigations are likely to provide much controversy and thrust the former Metropolitan Police Commissioner back into the spotlight.
Already famed for his extensive inquiries involving Northern Ireland's security forces, Lord Stevens, aged 64, was awarded a life peerage on his last day in the police's top job, at the end of January 2005.
The extrovert, 6ft 3in, policeman served for 42 years and was knighted in 2000.
He has been known as the "copper's copper" and also "Captain Beaujolais" because of his love of champagne and fine wines.
His report into the death of Princess Diana, the cost of which is estimated to be around £2m, is due shortly.
In May 2006 he hit the headlines again with comments about the investigation, called Operation Paget, stating that new evidence and witnesses had emerged, but declined to give further details.
He also said "we have to do a job that draws a line under this, one way or another".
And in March, Lord Stevens also began an investigation into football transfer dealings conducted between 1 January 2004 and 31 January 2006, an inquiry which is estimated to have cost more than £600,000.
So far he has found that 39 deals out of the 362 scrutinised need to be further investigated. The transfers involved eight of the 29 clubs that had been part of the top-flight during the span of his inquiries.
It was in the wake of the 2004 Madrid bombs that Lord Stevens said there was an "inevitability" terrorists would succeed in attacking London at some point.
As Met commissioner at the time, he described his awesome task as to do everything "to make sure that doesn't happen".
He always had a reputation as a straight-talking police chief and held numerous posts across the country's police forces before he was named commissioner at Scotland Yard in 1999.
After graduating with a degree in law, his first posting was as a beat officer with the Metropolitan Police in north London's Tottenham.
He quickly began to rise through the ranks and has received 27 commendations for his detective work.
It was during his time as deputy chief constable at Cambridgeshire in 1989 that he was asked to begin his first of three inquiries into the security forces in Northern Ireland.
That inquiry led the police chief into the hidden world of Northern Ireland's security forces and the violence played out in the shadows of the Troubles.
It resulted in 43 convictions and over 800 years imprisonment for those convicted.
Lord Stevens' second inquiry in Northern Ireland began in 1993, but it was his third appointment in 1999 that was the most critical - an inquiry focusing on the killing of Belfast solicitor Pat Finucane.
After investigating the killing he concluded there had been collusion between security forces and loyalist paramilitaries.
The South African, Jamaican, Bulgarian, Romanian, Qatar and Greek governments have all sought to share Lord Stevens' knowledge on policing issues.
Among his achievements is the creation of Convoy 2000, a charity set up to improve the quality of life for Romanian orphans, people with Aids and disabled children. He also holds pilot licences for multi-engine and single jet aircraft.