Security officials are investigating whether Russia was behind arson attacks on homes linked to Keir Starmer, according to reports.
Two Ukrainians and a Romanian man have been charged over the fires at two properties, including the prime minister’s home in north London before he moved to Downing Street, and a car he sold last year.
The suspects are accused of conspiracy to commit arson with intent to endanger life over the attacks earlier this month. Now officials are said to be probing whether the trio could have been recruited by Vladimir Putin’s Russia, senior Whitehall sources told the Mail on Sunday and Sunday Mirror.

Builder Roman Lavrynovych, 21, an aspiring model and Ukrainian citizen living in Sydenham, south London, was charged last week with three counts of arson with intent to endanger life.
Ukrainian-born Romanian national Stanislav Carpiuc, 26, also an aspiring model, was arrested by counterterrorism officers at Luton airport last Saturday and charged with being part of the conspiracy.
Petro Pochynok, 34, who calls himself a fashion entrepreneur on social media, was arrested in Chelsea, west London, on Monday.

At an earlier hearing, prosecutor Sarah Przybylska told Westminster Magistrates’ Court the court “at this stage the alleged offending is unexplained”.
All three deny the charges and have been remanded in custody to appear at the Old Bailey on 6 June.
It comes after three fires hit property linked to Sir Keir, including a vehicle fire in Kentish Town on 8 May targeting a Toyota Rav4 he had sold to a neighbour, a fire at the entrance of a property in Islington on 11 May, and one at his former home in Kentish Town on 12 May.

The Met’s Counter-Terrorism Command has led the investigation into the fires because of the links to the prime minister.
The force declined to comment on the possible links to Russia because criminal proceedings are active.
However, an intelligence source told the Sunday Mirror: “Russian involvement was the first option that was considered after these incidents took place.
“There is a pattern in the past of incidents here taking place on the Kremlin’s authority and then being very flimsily covered up, if covered up at all.”