Sergeant Matt Ratana would still be alive today if an "arrogant" rookie police officer had searched his killer properly when arresting him, an inquest has heard.
Pc Richard Davey, a probationer who had not completed his training, admitted that he failed to follow basic police procedure, missing a gun hidden under Louis De Zoysa's coat.
Double-jointed De Zoysa, 26, was able to shoot Sgt Ratana with the ten-inch antique revolver after smuggling it into a custody centre in Croydon, South London, while handcuffed behind his back.
The autistic former computer coder for HM Revenue and Customs was stopped on the street on September 25, 2020 at 1.30am by Pc Davey and Pc Samantha Still who found seven homemade bullets in a breast pouch.
But Pc Davey did not search De Zoysa according to the "top-down" training he had been given, failing to check the upper back or remove his jacket, the inquest at Croydon town hall heard on Wednesday. Dominic Adamson, KC, for Sgt Ratana's partner Su Bushby, who was in the hearing, asked the officer: "If you had done your job properly sergeant Ratana would still be alive wouldn't he?" Pc Davey, a former soldier who had been with the Met for 18 months at the time of the incident, replied: "I don't know."
Inside WW1 military hospital abandoned for decades before new lease of lifeMr Adamson added: "The gun would have been found, it would have been taken off him if you had done a proper search?" The officer answered: "I don't know how to agree with you on that, there's no way you could know." Coroner Sarah Ormond-Walshe stopped Mr Adamson, saying he had "gone a little too far", when he said Pc Davey had been described as "arrogant" in a witness statement.
Having been shown footage of the arrest in London Road, Norbury, Pc Davey was asked by Mr Adamson if he agreed that he had "abandoned basic good practice" during the search. The officer replied: "Yes." Asked if he accepted that he had not done an adequate search of the upper back, Pc Davey said: "I accept that. The weapon was there, I should have found it."
The officer had earlier told the hearing that he had decided to "deviate from the policy" and search De Zoysa's pockets first because he had repeatedly touched them. He said: "I was thinking about trying to find the firearm and was hell-bent on doing as thorough search as I could."
Pc Davey admitted his failure to find the gun was human error but added that he did not know if this was partially caused by him using "non-standard" search techniques. He also admitted to failing to monitor De Zoysa when he was seen in footage wriggling and jerking in a police van, which according to expert evidence was him repositioning the firearm to his hands. The officer further accepted that he did not hold De Zoysa by the arm while escorting him to a holding cell as he should have done.
He said: "Having seen the body-worn footage, I should have adopted Metropolitan Police policy." Pc Davey later added: "If I was to go back I would have done everything by the book." Sgt Ratana, who had served in the Met Police for almost 30 years and was three months from retirement, was hit in the chest by the first of three shots discharged by De Zoysa within three seconds.
A second bullet struck the New Zealand-born officer in the thigh before De Zoysa was wrestled to the ground by other officers, as a third round hit the cell wall. De Zoysa, who was living in a flat on a farm in Banstead, Surrey, discharged a fourth shot while on the cell floor, hitting an artery in his own neck and causing him brain damage. He is serving a whole-life jail term for Sgt Ratana's murder after a trial earlier this year.
The three-week inquest continues.