The prime minister made a “brief error of judgment” by removing the safety device as he promoted his levelling-up funding in the clip filmed for Instagram on Thursday.
A Downing Street spokesman said Mr Sunak “fully accepts this was a mistake and apologises … The prime minister believes everyone should wear a seatbelt”.
The PM’s spokesman added: “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.”
Fines of up to £500 can be issued for failing to wear a seatbelt when one is available. There are a few exemptions, including when a car is being used for police, fire and rescue services and for certified medical issues.
Labour said Mr Sunak’s video was adding to “endless painful viewing” after he was previously seen struggling to make a contactless payment with his card in a petrol station.
“Rishi Sunak doesn’t know how to manage a seatbelt, his debit card, a train service, the economy, this country,” a Labour spokeswoman said. “This list is growing every day, and it’s making for endless painful viewing.”
Liberal Democrat deputy leader Daisy Cooper said: “It seems like the PM is getting too used to flying around in private jets that he’s forgotten to wear a seatbelt in a car. The fact he’s breaking a basic law is just embarrassing and frankly dangerous.”
The AA also warned of the dangers of not wearing a seatbelt. “No matter who you are it is important to wear your seatbelt when in the car,” an AA spokesman said.
Police motorbikes can be seen escorting the car as Mr Sunak addresses the camera. Lancashire Constabulary referred a request for comment to the Metropolitan Police.
The government has considered toughening seatbelt rules to ensure drivers not wearing them could receive penalty points. Recent officials figures suggested around 30 per cent of people killed in cars on Britain’s roads in 2021 were unrestrained.
Mr Sunak had already been criticised for flying to Blackpool in a taxpayer-funded RAF jet rather than taking a train, as he carried out a series of visits to the north of England linked to levelling up funding.
Labour accused Mr Sunak of “jetting around the country on taxpayers’ money like an A-list celeb” and making a “mockery” of his environmental strategy after the 41-minute flight on Thursday.
Lib Dem deputy leader Daisy Cooper said: “It is simply ridiculous that he can’t get a train like the rest of the British public do. Yet again, this prime minister is completely out of touch with the rest of society.”
Asked about it at a Q&A session in Morecambe Mr Sunak said: “I travel around so I can do lots of things in one day, I’m not travelling around just for my own enjoyment – although this is very enjoyable, of course … I travel to make myself as effective as possible.”