Downing Street will be hoping that once the prime minister has paid up, voters and journalists will move on and forget this rather embarrassing unforced error.
But it is a reminder that in the top job, with a permacrisis of strikes, NHS delays and high inflation, mistakes can slip through the Number 10 net.
Failing to wear a seatbelt is illegal, but filming it and publishing the evidence on social media suggests a lack of checks within the PM’s team.
This is the second police fine Mr Sunak has received in nine months, after the Metropolitan Police punished him for attending a lockdown-busting birthday gathering for Boris Johnson.
In recent months Mr Sunak has struggled with contactless payments, had an awkward conversation with a homeless man about financial services, and demonstrated a fondness for using private jets to travel around the UK even for relatively short journeys.
Added together, such slip-ups may be exploited by the PM’s enemies to claim he is out of touch.
There is certainly a danger these small missteps distract from Mr Sunak’s attempts to stabilise the economy and sort out seemingly intractable issues like migrant crossings and delayed discharges.
Like many occupants of Number 11, Mr Sunak was a “submarine chancellor”. Invisible below the waves for months on end, he occasionally rose from the deep to launch a killer economic intervention: his “whatever it takes” COVID budget, the furlough scheme, Eat Out To Help Out.
But as Gordon Brown (the last politician to move from 11 to 10) found, similar manoeuvres are not possible as prime minister.
You are constantly in the spotlight. And it is an unsparing existence.