Man, 26, apprehended at Luton airport by counter-terrorism police in connection with fires that included damage to a car

A second man has been arrested in connection with suspected arson attacks on two properties in London and a vehicle linked to Keir Starmer, police have said.

The 26-year-old was arrested at about 1.45pm on Saturday at London Luton airport on suspicion of conspiracy to commit arson with intent to endanger life, the Metropolitan police said.

The arrest was made by counter-terrorism officers from the Eastern Region Special Operations Unit, and the suspect has been taken into police custody in London, the force added.

Officers from the Met’s counter-terrorism command have led the investigation into the three incidents.

One was a fire at the prime minister’s family home in north-west London, which he lets to his sister-in-law, the Guardian understands. The blaze was reported to police by firefighters in the early hours of Monday. Police said damage was caused to the property’s entrance but nobody was hurt.

A car that Starmer had sold to a neighbour last year was set alight four days earlier on the same street.

On 11 May, firefighters dealt with a small fire at the front door of a house where the Labour leader is understood to have lived in the 1990s before it was converted into flats. One person was helped to safety by firefighters wearing breathing apparatus, the London fire brigade said.

Anyone with information that could assist the investigation has been asked to contact the Met.

A 21-year-old man, Roman Lavrynovych, has already been charged with three counts of arson with intent to endanger life and appeared in court on Friday.

The Ukrainian national was remanded in custody after appearing at Westminster magistrates court. He did not enter any pleas to the charges.

Lavrynovych will appear next at the Old Bailey for a plea and trial preparation hearing on 6 June.