A second man has been arrested in connection with fires at two properties and a car linked to Prime Minister Sir Keir Starmer.
The 26-year-old was arrested around 1.45pm at Luton Airport on suspicion of conspiracy to commit arson with intent to endanger life.
The arrest was made by counter terrorism officers. The man has been taken into police custody in London.
It comes after a Ukrainian man, 21, was charged with three counts of arson with intent to endanger life.
Roman Lavrynovych appeared at Westminster Magistrates' Court on Friday and was remanded in custody.
Officers from the Metropolitan Police's Counter Terrorism Command led the investigation because of the connections to the prime minister.
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.
There was another blaze at the front door of a house converted into flats in Islington, also linked to the prime minister, on Sunday.
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One person was taken to safety via an internal staircase by crews wearing breathing apparatus.
Speaking of Lavrynovych, the head of the Crown Prosecution Service counter terrorism division, Bethan David, said: "These charges relate to two fires at residential addresses in Islington on Sunday May 11 and in Kentish Town on Monday May 12, as well as a car fire in Kentish Town on Thursday May 8.
"The Crown Prosecution Service reminds all concerned that criminal proceedings against this defendant are now active and that he has the right to a fair trial."
(c) Sky News 2025: Man arrested at Luton Airport in connection with fires at properties linked to Sir Keir Starme
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