A minicab driver is fighting for his life after suffering a suspected heart attack when a group of thugs followed his vehicle and smashed the windows.
The man in his 40s was ambushed by "four to five armed men" who had been following him moments earlier, police believe.
The victim tonight remains in hospital in a "critical condition".
A 999 call was made just after 11.30pm on Saturday reporting a group of males were damaging a Toyota Prius in Hackney.
Police and paramedics raced to the scene where they found the taxi driver inside the car suffering from a "medical episode".
Detectives believe it was a "planned attack" and the victim's car had been followed by a white Ford Focus.

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The Ford Focus is understood to have boxed in the cab before "four or five males armed with weapons" jumped out.
The thugs smashed the windows of the victim’s car before fleeing in the Ford Focus.
Three passengers who were also inside the minicab at the time of the attack were uninjured.
Detective Constable James Readman said: “Although the driver was not injured directly by the suspects, it is believed he was taken ill shortly after the attack on the car.
"He now remains in hospital in a life threatening condition and my officers are working to identify the group of males responsible.
“It appears this was a planned attack and an investigation has been launched to establish the full circumstances which led to this incident taking place.”
Anyone with information is asked to call police on 101 quoting CAD 8702/30March or Crimestoppers anonymously on 0800 555 111.