The Metropolitan Police said a 34-year-old was arrested this morning in the Chelsea area of west London on suspicion of conspiracy to commit arson with intent to endanger life.
On Saturday, a 26-year-old man was arrested at Luton Airport on suspicion of conspiracy to commit arson with intent to endanger life.
He is currently still in police custody after a warrant of further detention was obtained at Westminster Magistrates’ Court.
A 21-year-old man has been charged with three counts of arson with intent to endanger life and appeared in court.
Emergency services were called to a fire in the early hours of Monday at a house in Kentish Town, north London, where Sir Keir lived with his family before the election.
Damage was caused to the property’s entrance, but nobody was hurt.
A car was also set alight in the same street last Thursday.
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There was another blaze at the front door of a house converted into flats in Islington, also linked to the prime minister, on Sunday.
One person was taken to safety via an internal staircase by crews wearing breathing apparatus.
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