The police marksman who shot Chris Kaba has told a jury he thought one of his colleagues was about to die when he opened fire.

Giving evidence in public for the first time at the Old Bailey on Monday, Martyn Blake said he was “filled with dread” as the Audi Mr Kaba was driving moved backwards and forwards with police officers surrounding the car.

Mr Blake fatally shot Mr Kaba, 24, through the windscreen of the Audi in Streatham, south-east London on September 5 2022.

He told the jury that he felt “awful” following the shooting and has replayed events in his head since.

Asked what he was thinking immediately after the shooting, he said: “First of all I was relieved that the car noise subsided, relieved my colleagues were okay.

“Then I just felt awful.”

He told the court that since the shooting he thinks about what happened “every day, all the time”.

“I’ve been replaying it a lot,” he said.

I had a genuine belief that there was an imminent threat to life, I thought one or more of my colleagues was about to die

The court has already heard that when hemmed in by police cars, Mr Kaba, tried to ram his way past, between a marked police car and a Tesla parked nearby.

Mr Blake, 40, is accused of murder, which he denies.

He told the jury he could hear wheel-spinning and the car’s engine revving as armed officers tried to get Mr Kaba to get out of the car.

Mr Blake was asked by his barrister Patrick Gibbs KC why he had opened fire.

He said: “I had a genuine belief that there was an imminent threat to life, I thought one or more of my colleagues was about to die.

“I thought I was the only person with effective firearms cover at the time.

“If I hadn’t acted I thought one of my colleagues would be dead. I felt I had a duty to protect them at the time.”

He told the court he had aimed his gun above the steering wheel to give the best chance of hitting the central body mass of the driver, as officers are trained.

Asked by Mr Gibbs if he had intended to kill Mr Kaba, he replied: “No.”

He acknowledged that taking a shot into the central body mass at that range could be fatal.

Mr Kaba died from a gunshot wound to the head shortly after midnight on September 6 2022.

Mr Blake said he was aware that it was possible that one day he may have to shoot someone as a trained firearms officer.

But jurors were told: “Every officer in the department … thinks it will never happen to them.

“You hope it won’t happen to you.”

Members of Mr Kaba’s family sat in court listening to Mr Blake give evidence.

Working in firearms means that you face “the most dangerous and potentially the most violent” people in London, the officer told the court, adding: “It’s daunting but it’s a very rewarding job.”

Mr Blake described it as “probably the best job I would argue that you could have in the Metropolitan Police service, working with some of the best people I’ve worked with.”

Before he began giving evidence, Mr Gibbs told the jury: “He wants to give evidence, and you may think with a man dead it’s just the right thing to do.”

He said prosecutors have suggested either Mr Blake had a mistaken belief about risk, or took an unlawful decision to kill, but that there was a third possibility that he was right about the risk.

Mr Gibbs told the court the marksman opened fire because “he simply and honestly believed that he needed to”.

“Why else would he?” Mr Gibbs asked the jury. “Why else would anyone?

“He believed in the moment that the only way to negate a real and imminent threat to his colleagues was to do that momentous thing.”

The jury has already heard that fellow firearms officer DS87 said he would have opened fire if Mr Blake had not, and E156 who said he was fractions of a second away from doing so.

The trial continues on Tuesday.