A Metropolitan police firearms officer who shot an unarmed suspect in the head has been acquitted of murder. Sgt Martyn Blake shot Chris Kaba in September 2022 after stopping him on a residential street in Streatham, south London. Kaba, 24, was being followed while driving an Audi that police believed was linked to a firearms incident the previous evening. The unanimous not guilty verdict, which took just three hours to reach, fuelled police anger that Blake was ever put on trial. The decision to charge Blake, who had never fired a shot on duty before, had already infuriated his fellow firearms officers as well as the force’s commissioner, Mark Rowley. The commissioner called the system “broken” as his officer walked free from the Old Bailey on Monday, with police chiefs lobbying ministers to make it harder for such a trial to happen again. Police believe they have won a “policy package” from government, the Guardian understands, as they press for reform of a system which they claim punishes them for doing their job. Kaba’s family said they were “devastated” by the verdict in the face of “unimaginable grief”, with his supporters saying it gave police “impunity” to kill. His father, Prosper, had to be helped out of the courtroom after the verdict; another relative rocked back and forth. A visibly relieved Blake, 40, exhaled as the decision was read out, and hours later the Met said his suspension was lifted. He was flanked by police colleagues as he left the courtroom. The police watchdog will consider whether he should still face disciplinary action for gross misconduct, and an inquest looms. Scotland Yard remain on heightened alert in case of trouble and are closely monitoring community tensions. Dozens of people gathered near the Old Bailey on Monday evening, where a number of speakers demanded justice for Kaba and his family. A banner read: “We Keep Each Other Safe”. Other supporters held placards saying: “Justice for Chris Kaba”. Supporters chanted: “Say his name: Chris Kaba” and “no justice, no peace”. One of the speakers called for people to join a march on Saturday in central London, and said Kaba’s family would be there to hand a letter into 10 Downing Street. After the verdict, Rowley, who is struggling to recruit and retain enough officers for his embattled force, said: “Sgt Blake made a split-second decision on what he believed was necessary to protect his colleagues and to protect London. The jury decided that was an honestly held belief and the force used was reasonable. “Any fatal use of force understandably prompts huge concern among communities, particularly in Black communities where trust in policing is low … We know incidents like this place further strain on already challenged relationships. “No police officer is above the law, but we have been clear the system holding police to account is broken. I worry about the lack of support officers face for doing their best, but most of all I worry for the public. The more we crush the spirit of good officers, the less they can fight crime. That risks London becoming less safe.” Kaba’s family said: “The not guilty verdict leaves us with the deep pain of injustice adding to the unbearable sorrow we have felt since Chris was killed. No family should endure the unimaginable grief we have faced. Chris was stolen from us, and this decision shows his life – and many others like him – does not matter to the system. Our son deserved better. “The acquittal of Martyn Blake isn’t just a failure for our family, but for all those affected by police violence. Despite this verdict, we won’t be silenced. We will continue fighting for Chris, for justice, and for real change. Chris’s life mattered, and nothing can take that away from us.” Police stopped the Audi not knowing who the driver was, only that it was potentially linked to a shooting the night before. The vehicle Kaba had been driving was forced to stop and was then surrounded by armed officers, who burst out from three police cars and tried to pull the suspect out. Blake, who was in a police car that blocked the Audi from the front, said he opened fire fearing Kaba would pull an officer under its wheels or run them over, as their suspect tried to escape “at any cost” after being blocked in. He said the car was being used as a weapon and he had fired in self-defence and also to protect his colleagues, with his primary aim being to “incapacitate” the driver, who was hunched low over the steering wheel. The prosecution said the Audi was blocked within seconds and could not have escaped nor run over officers at the point Blake shot. The crown accepted that Kaba made “concerted” efforts to escape, but his Audi’s top speed during the standoff was 12mph. Scores of Met armed officers walked out when Blake was charged. The force feared a conviction could have led to a fresh and potentially bigger rebellion, and held discussions with army leaders about soldiers coming on to London’s streets. Temi Mwale and Kayza Rose, of the Justice for Chris Kaba Campaign, said: “This outcome reinforces the harsh reality that police can kill without consequence. No one can be safe while the police can kill with impunity.” The home secretary, Yvette Cooper, said: “The British tradition of policing by consent relies on mutual bonds of trust between the public and the police. It is important both that the police have the confidence of communities they serve and that officers have the support and confidence they need to do the difficult job of keeping us safe. The government is committed to working with policing to strengthen confidence for the future.” The criminal investigation was carried out by the police watchdog, the Independent Office for Police Conduct. Frank Ferguson, the head of the Crown Prosecution Service’s special crime and counter-terrorism division, said: “We recognise that firearms officers operate under enormous pressure, but it is our responsibility to put cases before a jury that meet our test for prosecution, and we are satisfied that test was met in this case. “It is therefore right that the case was put before the jury for them to scrutinise and to decide.”