The detained, a 34-year-old man, is suspected of involvement in the three incidents, all of which are being investigated as arson. Previously, a 21-year-old man and a 26-year-old man have been detained in the case, writes BBC.
The first fire broke out on May 8 in a car parked on the street in northwestern London where Keir Starmer has his private home. The car has previously been owned by Starmer, who is said to have sold it to a neighbor last year.
On May 11, the rescue service was alerted about a new fire, this time at an address where the Prime Minister previously lived.
A day later, it burned again, this time in Starmer's home on the same street as the car fire. The residence is rented out by Starmer since he moved into the Prime Minister's residence on Downing Street.
No personal injuries have been reported in connection with the fires.
