The report, which identified “systemic and fundamental problems” within the Met including “inadequate management”, made 16 recommendations that would constitute a “complete overhaul”.
London Mayor Sadiq Khan, who has responsibility for the force and initiated the review, said he expected all of them to be fully implemented quickly.
“It’s in all of our interests to make sure that the police service changes, root and branch,” he told the BBC.
“UNACCEPTABLE”
Failure to reform could mean the force, which polices more than eight million people over 1,605 sq km in the British capital, would be broken up, Casey warned.
“The bottom line is this, if an organisation can’t fix itself then there has to be change,” she told BBC radio.
But she noted: “The tougher thing is to ask the organisation to change its culture and to do a better job.”
The Met had failed to protect its female staff and the public from “police perpetrators of domestic abuse, nor those who abuse their position for sexual purposes”, her report stated.
“Time and time again, those complaining are not believed or supported. They are treated badly, or face counter-claims from those they have accused,” it said.
The 363-page review also said an “absence of vigilance” meant that “predatory and unacceptable behaviour has been allowed to flourish”.
Racism also exists within the force, with discrimination “often ignored” and complaints “likely to be turned against Black, Asian and ethnic minority officers”.
The Met’s investigations of crimes was also criticised, with the review saying that the force relied on “over-stuffed, dilapidated or broken fridges and freezers” to store forensic evidence.
A lunchbox was found in the same fridge as forensic samples in rape cases, and some appliances were so full they were strapped shut.
One fridge broke down, meaning the evidence inside could no longer be used, the report found.