A police officer accused of murder gave a “false” and “exaggerated” account to justify shooting dead an unarmed man in a stationary car, a jury has been told. Martyn Blake, a Metropolitan police firearms officer, was accused of getting key details of his account wrong after shooting Chris Kaba once in the head. Kaba had been the driver of an Audi car linked by police to a firearms incident the day before. Police decided to stop the car as it travelled through south London on 5 September 2022 and detain the driver. Blake, 40, on trial at the Old Bailey in central London, denies the murder of Kaba, 24. His barrister, Patrick Gibbs KC, said Blake had fired fearing his colleagues would be killed as the Audi tried to ram its way out of being penned in by police and parked cars. Gibbs said the officer feared Kaba would try to escape “at any cost” and would use his two-tonne car as a weapon to run over officers trying to pull him out of the Audi. The jury were shown video from police body worn cameras and a helicopter as well as graphic reconstruction of where officers were positioned. Tom Little KC, prosecuting, said “unassailable footage” disproves key parts of Blake’s accounts that the officer made after the shooting. Police cars were blocking in the Audi at front and rear. After Kaba tried to break out they tightened the blockade, which the prosecutor said meant there was little or no space for any escape to take place. Blake had claimed the Audi attempted to break out at great speed, but its onboard computer showed the greatest speed it achieved was 12mph. Little said: “We say that the use of force was not necessary … and that his version of events is false and exaggerated.” Little outlined what the prosecution argues are the key questions for the jury: “First, was the use of force necessary in the circumstances and with the danger the defendant genuinely believed them to be? “Second, was the level or degree of force used reasonable in those circumstances?” Gibbs said Kaba tried to “ram” his way out when boxed in and did not care what the consequences were, with officers having burst out of the cars and surrounding his vehicle. Some made attempts to break his windscreen with the muzzle of their guns, to enact a plan to extract him from the Audi. Gibbs said Blake was acting as firearms cover, armed with a Sig Sauer MCX 5.56 rifle, as his colleagues tried to detain Kaba. Gibbs said the jury and lawyers in court had the benefit of hindsight: “He was doing his honest best, according to his training, to interpret what he was seeing and anticipate what would happen if he didn’t fire in a 17-second incident.” In a statement after the shooting, Blake said: “The male had already shown a propensity to use violence and was happy to use any means to escape and I had a genuine held belief that one or many of my colleagues could be killed by the car, and that the driver would not stop his attempt to escape at any cost. “I then made the decision to incapacitate the driver due to the imminent threat to my colleagues and took one shot at the driver. He immediately slumped and the car stopped.” The trial, scheduled to last three weeks, continues.