In the clip, which lasts around a minute, Mr Sunak can be seen addressing the camera while the car travels along, with police motorbikes briefly appearing in the background.
Passengers caught failing to wear a seat belt when one is available, unless covered by a valid exemption, can be given an on-the-spot £100 fine. The fine can increase to £500 if the case goes to court.
'Painful viewing'
Labour said Mr Sunak's video added to "endless painful viewing" after he was seen struggling to make a contactless payment with his card last year.
"Rishi Sunak doesn't know how to manage a seat belt, his debit card, a train service, the economy, this country," a spokeswoman said.
"This list is growing every day, and it's making for endless painful viewing."
The incident followed criticism of the prime minister for travelling in an RAF jet for a series of official visits on Thursday.
Mr Sunak made the 230-mile journey to Blackpool from London in the plane, before later flying 120 miles to Darlington.
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 seat belt in a car."
'Politically motivated'
But Conservative MP for Blackpool South Scott Benton suggested the Lancashire force were wasting their time by looking into the incident.
He said: "The vast majority of people would think that politically motivated complaints about a seatbelt are not good use of frontline resources.
"Their time is better spent investigating serious crime which impacts on my constituents."
Labour said it would be "very serious" if Mr Sunak was to be fined, having already had to pay a fixed-penalty notice while he was chancellor during the Partygate scandal.
Passengers aged 14 and over are responsible for ensuring they wear a seat belt in cars, vans and other goods vehicles if one is fitted. Drivers are responsible for passengers under 14.
Exemptions include having a doctor's certificate for a medical reason, or being in a vehicle used for a police, fire or other rescue service.
Those who are fined for not wearing a seat belt can not currently be given penalty points on their licence, except in Northern Ireland.
But in October, Transport Minister Katherine Fletcher said the government was considering introducing penalty points in England.
"In 2021, in 30% of all car occupant fatalities recorded, seat belts were not worn. This is unacceptably high," she told Labour MP Barry Sheerman.
RISHI Sunak membuat ucapan di dalam kereta yang sedang bergerak tanpa memakai tali pinggang keledar.-AGENSI
Oleh WARTAWAN LUAR NEGARA
20 Januari 2023, 9:30 pm
LONDON: Polis akan meneliti video dimuat naik Perdana Menteri Britain, Rishi Sunak selepas beliau dikecam kerana dikatakan tidak memakai tali pinggang keledar ketika berada di dalam kereta yang sedang bergerak.
Lapor Mirror UK, jurucakap Sunak yang menyiarkan video itu di media sosial berkata, kesilapan itu tidak disengajakan dan Sunak telah memohon maaf berhubung perkara tersebut.
“Perdana Menteri percaya semua orang harus memakai tali pinggang keledar dan sekali lagi, saya rasa saya telah menjelaskan bahawa terdapat sedikit salah faham.
“Beliau hanya mencabutnya untuk tempoh yang singkat ketika merakam klip video tersebut tetapi beliau menerima perkara itu sebagai satu kesilapan dan memohon maaf,” kata jurucakap itu.
Sunak memuat naik video yang dilaporkan dirakam di Lancashire melalui akaun Instagram rasminya yang mempunyai 1.3 juta pengikut.
Dalam video itu, Sunak berucap dengan nada gembira mengumumkan butiran kenaikan peruntukan dana untuk rakyat yang dikeluarkan kerajaan pimpinannya.
“Secara keseluruhan, kami mengumumkan lebih 2 bilion pound (RM10.6 bilion) pembiayaan yang akan digunakan untuk menyokong projek di 100 komuniti tempatan berbeza di seluruh United Kingdom (UK). Kini saya keluar dan melihat progresnya di seluruh negara.
“Anda boleh mengikuti perkembangan saya semasa saya mengelilingi negara hari ini secara dalam talian atau pergi ke laman web Kerajaan di mana anda boleh melihat peta interaktif semua yang kami lakukan,” ucapnya dalam video berkenaan.
Ramai warga net secara sinis meluahkan rasa bimbang dan mempersoalkan sama ada Sunak memakai tali pinggang keledar sepanjang perjalanan itu.