Profile: Ex-Met officer John Yates
Assistant Commissioner John Yates joined the Metropolitan Police in 1981, spending time both in uniform and as a detective.
He went on to lead investigations into more than 20 murders.
His portfolio at the Met included police complaints, intelligence, legal matters and specific high-profile police investigations.
His experience ranged from senior involvement in investigating police corruption, to probing the "cash-for-honours" row, to leading the UK policing response to the Asian tsunami on Boxing Day 2004.
The 52-year-old's CV also includes knowledge of investigating rape, street crime, organised criminal networks and gun crime.
The senior policeman worked as staff officer to Met Commissioner Paul Condon during the period of the Macpherson Inquiry into the death of black teenager Stephen Lawrence between 1999 and 2000.
In the same years Mr Yates' reputation was further cemented when, as a detective superintendent, he led a massive internal police corruption inquiry into 9 Regional Crime Squad, based in East Dulwich.
It ended with six serving narcotics detectives being jailed for a drugs conspiracy.
Mr Yates further established his reputation as a robust operator capable of handling cases in the media spotlight with his involvement in the perjury case of Lord Archer, as well as the failed prosecution of royal butler Paul Burrell and the Who Wants to be a Millionaire fraud trial.
Following the Boxing Day tsunami he headed Operation Bracknell, which opened a bureau to log details of those missing, describing it as an "unprecedented challenge". His achievements during the tsunami response led to him being awarded the Queen's Police Medal (QPM).
He also went on to lead the Met's response to the shooting of Jean Charles de Menezes at Stockwell Tube station, in the wake of the July 2005 London bombings.
The 2006 inquiry into whether peerages were offered in return for party donations was one of his toughest and most sensitive challenges.
The police investigation, during which more than 130 people were interviewed and four people were arrested, focused on allegations that peerages had been offered in return for loans to Labour and the Conservatives ahead of the 2005 general election.
No charges were brought following the 16-month police inquiry.
Mr Yates was made assistant commissioner in December 2006 and took over as head of counter-terrorism at Scotland Yard after the resignation of his colleague Bob Quick over a security blunder in 2009.
Scotland Yard's first inquiry in 2005 and 2006 into News of the World phone hacking resulted in the conviction of the newspaper's former royal editor, Clive Goodman, and private investigator Glenn Mulcaire.
Following fresh allegations made by the Guardian in July 2009, Mr Yates was asked to establish the facts and consider reopening the investigation.
He concluded that the information was not new evidence and the inquiry was not reopened. His decision was endorsed by the Director of Public Prosecutions, Keir Starmer.
On 26 January 2011 the Met announced it was reopening its inquiry into phone-hacking allegations.
It said it was no longer appropriate to divert the counter-terrorism branch or Mr Yates from their main duties in view of their workload and the threat level to the UK.
But in July of that year Mr Yates became aware that he was to be suspended pending an inquiry into his relationship with Neil Wallis, the ex-News of the World executive, arrested over phone-hacking allegations.
The two men have known each other for many years.
Knowledge of his impeding suspension prompted the highly-regarded police officer to resign from his post.