No-one will be prosecuted over claims that detectives tortured and abused two suspects during a drugs raid.
Prosecutors said there was insufficient evidence to charge any of the members of Enfield crime squad, in north London.
One suspect claimed he was assaulted during a raid at an address in Tottenham in November 2008.
A second man alleged he was effectively "waterboarded" as his head was held in a toilet as it was flushed repeatedly.
Prosecutors added that no-one from the unit would be charged over further claims they used excessive force to stop a stolen car.
But they said officers did flout internal procedures on the handling of goods recovered from offenders.
Investigators found officers kept high value electrical items, believed to include plasma TVs, at their police station.
Simon Clements, of the Crown Prosecution Service (CPS), said the two suspects were inconsistent, they identified the wrong officers and there was no medical evidence.
He said: "In the absence of reliable, corroborative evidence there is no realistic prospect of a conviction against any officer.
"Put simply, events could not have happened as the two men described them."
The decision came after a file of evidence was passed to the CPS by the Independent Police Complaints Commission (IPCC) and the Met's Directorate of Professional Standards.
A total of 15 members of Enfield's crime squad were investigated over the assault allegations and claims that seized personal property was misappropriated.
As well as plasma TVs, police were accused of taking a Mercedes car from a criminal suspect for their personal use.
Independent investigators also examined an incident in June 2008 when it was claimed police used "excessive force" to stop a disqualified driver in a stolen car.
But prosecutors said the driver would not help the misconduct inquiry and police justified their actions by saying he was dangerous with a history of carrying weapons and assaulting officers.
Mr Clements said: "In those circumstances it was impossible to prove that the force used was not proportionate or reasonable."
The investigation also examined abuse of a system in which suspects can "disclaim" ownership of property found in their possession.
Prosecutors said this had been used to "circumvent" formal police procedures for the seizure of criminal property.
Mr Clements said officers claimed their managers were aware of their actions and supported it.
He said: "There was no evidence that the seized items were put to officers' personal use, rather than deployed in police-related activities."
Mr Clements added that senior managers admitted they were "generally aware" of what was happening and there was not enough evidence to prosecute them either.
He said: "Their evidence also means that we could not charge the officers with theft because, given the open way their actions took place within the police station, we would not be able to prove they acted dishonestly.
"For the same reason they could not be charged with misconduct in public office as recent case law shows where the substance of the allegation under consideration is the dishonest appropriation of property, we would need to prove they had acted dishonestly to prove that offence too.
"It is clear that internal police procedures were flouted and breached on a regular basis.
"But we cannot prosecute members of a squad unless we can show to the criminal standard that they acted dishonestly."
Suspicions arose over the behaviour of the officers, who included a detective sergeant, shortly after the raids on November 4 2008.
In February 2009, Scotland Yard said nine officers from the squad had been suspended and two placed on restricted duties, effectively shutting it down.
But the scope of the probe widened when shocking new information alleging that the suspects were tortured came to light.
Officials at the IPCC took over the internal inquiry on April 3 after further allegations of mistreatment were made.
The most serious was a claim some of the men were effectively "waterboarded" during questioning at the Tottenham property.
The simulated drowning technique became notorious after its use by United States CIA interrogators on Guantanamo Bay terror suspects.
It involves pouring water on to cloth or plastic held over the victim's face, causing them to feel as if they are suffocating.
Nigerian Nnanyere David Nwankwo, 24, told friends he was kicked and pushed in the toilet by officers during the raid at his home in Brantwood Road, Tottenham.
A second man, Ajah Mpakaboari, 33, was left bleeding after he was also allegedly assaulted during a search.
A third Nigerian connected to the address, Bernasko Adji, 36, was charged with assaulting a constable during the raid.
But the charge, and a drug smuggling case against the trio, and a man and a woman held at a second address in Enfield, was dropped by prosecutors.
They said proceeding with it could prejudice the wide-ranging inquiry into suspected criminal activities by a number of officers.
A second team of officers arrested Victoria Seabrook, 24, and Nicholas Oforka, 25, at another property in Hertford Road, Enfield.
Commissioner Sir Paul Stephenson appointed a new borough commander in Enfield as the claims provoked outrage.
A Met spokesman said the investigation has been "extensive and complex" as a result of the variety of allegations and alleged incidents.
There were inquiries into three claims of assault, one into claims laws governing surveillance were broken and a further inquiry into mishandling of property.
The spokesman said eight officers remain suspended while senior officers consider the prosecutor's decision and consider misconduct proceedings.
He said: "As part of examining what lessons could be learnt, we have looked at the property handling process on the borough and more widely across the Met to identify where improvements can be made.
"The Directorate of Professional Standards has worked with other Met departments to ensure that crime property handling processes are improved.
"The Met does not tolerate conduct that falls below the standards the public and the many outstanding officers and staff expect and any allegations of behaviour that is contrary to the police regulations are treated very seriously.
"It is only right such allegations are investigated by the Directorate of Professional Standards or the IPCC when appropriate, such as in this case.
"Other officers on Enfield borough have been carrying out the role of the crime squad to ensure police locally are tackling the criminals that cause a problem for the community."