Police are “looking into” whether Rishi Sunak broke the law after the prime minister was filmed in a moving car without wearing a seatbelt.
Sunak earlier apologised as Downing Street said he had made a “brief error of judgment” by removing the safety device when he visited Lancashire on Thursday.
Fines of up to £500 can be issued for failing to wear a seatbelt when one is available.
A spokesperson for Lancashire Police said: “We are aware of the matter and we will be looking into it.”
A Downing Street spokesperson said Sunak “fully accepts this was a mistake and apologises”.
“The prime minister believes everyone should wear a seatbelt,” the spokesman said.
“It was an error of judgment, he removed it for a short period of time to film a clip, which you’ve seen, but he accepts that was a mistake.”
There are a few exemptions for failing to wear a belt, including when a car is being used for police, fire and rescue services and for certified medical issues.
But Downing Street did not believe there was an exception for travelling in a ministerial car.
The government has considered toughening seatbelt rules to ensure drivers not wearing them could receive penalty points.
Recent Department for Transport figures suggested around 30% of people killed in cars on Britain’s roads in 2021 were unrestrained.
Sunak was also facing criticism for travelling to Blackpool in a taxpayer-funded RAF jet rather than using a train, and then taking a 28-minute flight to Darlington.