A Metropolitan Police marksman may have been “angry, frustrated and annoyed” when he took the decision to shoot to kill Chris Kaba, a court has heard.

Martyn Blake, 40, has gone on trial at the Old Bailey charged with murdering Mr Kaba.

The 24-year-old was in the driving seat of an Audi car when he was shot in the head in Streatham, south London, on September 5 2022.

Prosecutor Tom Little KC told jurors Blake’s decision to use lethal force was “not reasonably justified or justifiable”.

He told jurors: “The defendant did not know the man he shot. What he was thinking at the time only he knows.

“But you may want to consider in this case whether the requests that were made to Chris Kaba by the police that he did not obey caused the defendant to become angry, frustrated and annoyed.”

Opening the case on Wednesday, Mr Little said: “This case involves a decision by this defendant to shoot Chris Kaba with the intention to kill. It was a decision taken to use lethal force with a firearm by a firearms officer in the Metropolitan Police.

“It was a decision to shoot which was taken when, we say, the unassailable evidence of what actually took place that night reveals that it was not reasonably justified or justifiable.”

It should be a “remedy of last resort” for a firearms officer to shoot and kill, jurors were told.

But the prosecutor said: “The body-worn footage and footage from cameras on police vehicles reveals, we say, that it was not necessary to shoot.

“The immediate risk to both the defendant and his fellow officers at the scene did not, we say, justify at the point when the trigger was pulled, firing a bullet into the vehicle that Chris Kaba was driving .

“That is why, we say, that this is a case of murder rather than the use of lawful self-defence or lawful defence of another by the defendant.”

At the point Blake shot Mr Kaba in the head, the vehicle he was in was stationary, jurors heard.

The young man had just reversed a short distance backwards, striking the front of a police vehicle that was blocking it in, having previously attempted to drive forwards, jurors heard.

Mr Little said: “We say that on careful analysis nothing Chris Kaba did in the second before he was shot justified this defendant’s decision to shoot.”

Members of Mr Kaba’s family, including his parents, sat in the well of the court just metres from Blake in the dock, as Mr Little laid out the case for the prosecution.

Mr Kaba’s mother Helen Lumuanganu became visibly upset and was comforted by a relative as video footage of armed officers swarming around the Audi was played in court.

Mr Little said that the situation was difficult and challenging, but added: “The reality is that the defendant discharged his firearm at the point that the vehicle that Chris Kaba was in was stationary and when there were no officers directly behind the vehicle and the prospect of him being able to escape was not obvious.”

A firearm marker was placed on the Audi after its registration was linked to an incident the evening before in which members of the public had contacted police to report gunshots in Brixton, the court was told.

Blake has denied murder and the trial before Mr Justice Goss was adjourned until Thursday.