Handheld metal detectors could be rolled out by forces across the country after the murder of custody sergeant Matt Ratana inside a police station holding cell, a watchdog has said.
Louis De Zoysa, 25, was found guilty of killing Sgt Ratana, 54, after shooting him with a hidden revolver, which was not found during an initial search, while he was handcuffed in a holding room at Croydon's Windmill Road custody block on September 25 2020.
The Independent Office for Police Conduct (IOPC) said its recommendation to use the search wands in all response vehicles and vehicles used to transport detainees had been accepted and the National Police Chiefs' Council is looking into the implementation.
Since Sgt Ratana's death, the Met has issued more than 4,000 handheld metal detectors to frontline officers, all frontline vehicles and all custody suites and piloted the use of full body scanners in custody suites, Deputy Assistant Commissioner Stuart Cundy said.
Expanding on new search measures in the Met, Mr Cundy said a "small number" of handheld metal detectors were in use in September 2020, but the force decided to escalate their use more widely, as rapidly as it could "deliberately within a matter of days" of Sgt Ratana's death.
He added that a full body scanner, similar to those seen at airports, has recently been installed in a custody suite in south London, saying the Met is the first police force in the UK to do so.
IOPC director of operations, Amanda Rowe, said the watchdog's investigation found the officers who initially searched De Zoysa would benefit from more training but commended them for their "incredible bravery" in trying to disarm him as he was shooting.
She said: "My thoughts continue to be with the family, friends and colleagues of Matt Ratana and all of those affected by this shocking incident.
"I hope the recommendation we have made will improve officer safety and help to prevent detained persons from being able to harm themselves or others in custody.
"We did find two officers could have conducted a more thorough body search of De Zoysa on the street, during which ammunition was found but not the firearm.
"Although the officers searching De Zoysa did not strictly follow MPS training, which requires that the torso is divided into quarters, and each quarter is searched from the top down, both back and front, we concluded that neither their actions nor omissions breached the police standards of professional behaviour.
"However, we suggested one officer could benefit from some further training around body searches and transportation of detainees, and the second officer around body searches and their role in assisting the other officer.
"There is no power for police to require a person to remove any clothing in public other than a coat, jacket or gloves.
"Searching officers can request the removal of outer clothing, but it is not mandated by the legislation, policy or guidance.
"Given that we now know De Zoysa wore a gun holster beneath his coat it is possible the search would have yielded different results if the coat was removed.
"The same officers should be commended for their incredible bravery in trying to disarm De Zoysa after he produced the firearm.
"They acted without hesitation, despite the significant danger they were placed in at the time."
The handheld metal detectors could be a screening device available to officers already conducting a lawful and justified physical search of a person following their arrest.
They should not replace the requirement for a physical search and should be used at the discretion of the officer conducting the search, taking into account the search powers relied upon and the grounds for the search, the IOPC added.