What happened
Ibrahima Sey was 29, a Gambian asylum seeker, and acutely mentally ill. In the early hours of 16 March 1996 his wife called police to their east London home because his behaviour had alarmed her, and a friend travelled with him to Ilford Police Station. He came out of the house without a struggle.
At the rear yard, officers refused to let the friend go in. While Sey was still asking for him, six to eight officers took hold, one in a bear hug from behind, took him to the ground and rolled him onto his stomach to cuff his hands behind his back.
Twice they tried to lift him and his legs gave way, leaving him face down and limp. On the third attempt, still on his knees and still cuffed, he was sprayed with CS around the nose and mouth. He was walked doubled over into the station, collapsed in a corridor, and carried face down into the custody suite, where four to six officers held him by head, arms and legs, two with their feet on his legs, for 15 minutes or more until he stopped breathing. The ambulance crew found him still handcuffed.
The outcome
The inquest jury sat at Snaresbrook Crown Court and returned a verdict of unlawful killing on 1 October 1997. It found the force so unreasonable and unnecessary as to make the death unlawful. Pathologists agreed the prone position would have impaired his breathing enough to cause death.
In 2001, according to Bhatt Murphy, the damages claim was settled for £45,000 in Sey v Commissioner of the Metropolitan Police.
What went wrong
The death happened in stages, and every stage had a decision in it. Separating him from the one person who was keeping him calm started it. Spraying CS at a handcuffed man on his knees, who had twice gone limp, added a respiratory stressor to someone already failing. Holding him prone for a quarter of an hour finished it.
The guidance existed. ACPO guidance in force for the CS trials said prisoners “must not be left in or transported in a prone face down position”, and required breathing to be monitored after spraying. Officers across the Met had already been warned about positional asphyxia after the deaths of Richard O’Brien and Wayne Douglas.
What it teaches
A person who goes limp each time you lift him is telling you what the position is doing to him. The lesson is that the second limp should have ended the attempt to get him upright and started a different plan.
Guidance that is not in the yard at two in the morning is not guidance. The document existed, and the force had issued warnings after two earlier restraint deaths. A trainer’s question is what would have had to be different for either to reach it.
Questions for the room
- He went limp twice before the spray. What should that sequence have triggered, and who was placed to notice it?
- You are the officer holding his legs with your foot. He stops resisting. What is your next action, and who do you tell?
- The guidance banned prone transport and required monitoring after CS. Which rule was broken first, and does the order matter?
Evidence and limits
Confidence: probable. The death, restraint sequence and unlawful-killing verdict come from INQUEST’s contemporaneous briefing. The £45,000 settlement rests on the claimant solicitors’ case list, which as fetched carries no Sey entry.
The pathological position is recorded rather than resolved: the provisional cause was revised, and the family’s experts gave positional asphyxia. An inquest verdict of unlawful killing is not a conviction, and the record has no criminal or disciplinary outcome.
Our physical interventions training covers positional risk, monitoring and the decision to stop.
Sources
Reviewed 20 October 2026.