Leaked documents show that in October 2013, some officers in Britain's largest police force were ordered to arrest a minimum number of people. Over the following six months, the Met issued two separate denials that any such instructions existed.
"It's a sad indictment of the ranking officers, though not of the coppers on the ground who suffer under them. And it raises yet more serious questions about the culture of unethical behaviour at Scotland Yard," said James Patrick, the former Met whistleblower.
Patrick, who resigned in March this year, said: "It is unsurprising that this was denied, because it would have meant an admission that those in the upper ranks held some responsibility. The Met has a well-established talent for reputation management and they use it regularly.
"If you can't trust them, what use are they to the public?"
His comments came after Channel 4 News discovered that it was made clear to a group of officers in a borough in October 2013 that they were expected to arrest at least two people every month, as well as to stop and search at least four. They were also ordered to issue at least one penalty notice or get a case to charge stage and to make a minimum of four entries in the force's intelligence database.
They were threatened with censure if they did not meet the targets. Police sources said the practice was common across the Met and still in place, a claim backed up by the Police Federation.
"The Met cannot be any clearer on this matter. We do not set officers targets for how they apply their powers of arrest and stop and search," said then Assistant Commissioner Simon Byrne in comments circulated internally in January. A public denial attributed to the force was also released that month.
Byrne himself issued a public denial in April this year after the Police Federation made similar allegations. But he conceded that, at a team level, work rate targets may have existed. Byrne is now the chief constable of Cheshire police, having left the Met in June 2014.
Former Met Police Assistant Commissioner Simon Byrne with London Mayor Boris Johnson
The leaked documents, however, show that targets were set and that the decision was taken at a chief inspector level. They also show that concerns about target setting were raised with senior officers before Byrne's public denial. But, according to a confidential police source, nothing was done.
In an email to colleagues back in October 2013, a Met police chief inspector wrote to his subordinates: "Following a meeting with the inspectors last week we have decided that every individual officer needs to be set a minimum expectation per month."
Officers were also told how to get "easy wins" by searching the force's database for warrants in their areas and making the arrests.
In an email sent in January - immediately after Byrne denied the Met set targets - a sergeant addressed his colleagues' belief that they would, therefore, no longer have to present their figures to their superior. "This is false," the email read.
Instead officers were reminded of their individual targets and told that they would be expected to account for it if they failed to arrest enough people. But the sergeant assured them that failure would not result in their being fired.
Chris Hobbs, who spent more than three decades with the Met police before retiring in 2011, said there were "huge risks" with imposing minimum targets.
He acknowledged that two arrests per month did not sound like a large number but said that, under the Met's local policing model, many officers spent long periods of time on duties that would not usually result in making an arrest, such as filing paperwork and attending reports of minor crimes they have been given particular responsibility for.
"There is a danger that people will be so desperate to fulfil their quota that they will arrest people to boost the figures when it is not necessary."
Former PC James Patrick, the constable who revealed the widespread manipulation of police-recorded crime statistics last year, agreed.
He said that arrests amounted to a deprivation of liberty and should not be made in pursuit of arbitrarily set quotas. "Targets are inherently dangerous, they result in perverse performance."
A Met police spokesman said: "The [force] has always made it absolutely clear that it does not centrally set officers individual targets, and that local managers should not be setting officers individual targets.
"Without Channel 4 providing detailed evidence of these claims, it is very difficult for the MPS to look into the matter."