A dramatic video shows a car going up in flames outside a north London home understood to be owned by Sir Keir Starmer.
The inferno in Kentish Town came just days before an alleged arson attack at the same house.
A 21-year-old man has been arrested over that fire, as well as another in the suburb of Islington.
The video shows flames billowing from the vehicle, which has been reduced to a charred shell, and firefighters using hoses to battle the blaze.
Counter-terrorism police are investigating whether the car fire is linked to the alleged arson attacks.