London's Metropolitan Police force said that counterterrorism officers were involved in the investigation.
Firefighters were called to “a small fire” just after 1 a.m. (0000 GMT or 8 p.m. EDT), the city's fire department said. Two engines responded, and the blaze was out within a half-hour.
Police said that officers who responded to the scene found damage "to the property's entrance," but that nobody was hurt.
“The fire is being investigated and cordons remain in place while enquiries continue,” the police force said.
A cordon of police tape was visible outside the house on Monday.
Starmer’s house has attracted protesters in the past. Last year, three pro-Palestinian activists were arrested and charged with public order offenses after unfurling a banner covered in red handprints outside the building.
Starmer's spokesman, Dave Pares, said that “the prime minister thanks the emergency services for their work.”
He said the fire "is subject to a live investigation, so I can’t comment any further.”
Credit: AP
Credit: AP