Passengers suffered a four-hour mouse delay Wednesday on a British Airways flight from London to San Francisco.

Fliers were already onboard the British Airways Boeing 777, which was readying to push back from the gate when the rodent-related ruckus began.

"Somebody saw a mouse that scurried under one of the doors," passenger Chris Claeboe said to ABC 7 of San Francisco. "They kept us on the plane for about 15 minutes, told us we had to get off the plane because we couldn't fly with a mouse."

Eventually, passengers on BA Flight 285 were put on a replacement aircraft, causing a delay of 4 hours and 16 minutes, according to British Airways’ website. The flight made up some time en route but still landed in San Francisco late, arriving 3 hours, 35 minutes past schedule.

British Airways acknowledged the disruption in a cheeky statement provided to Today in the Sky.

"With service and prices this good, we know almost everyone wants to fly with us to San Francisco," the carrier said. "But on this occasion there was one very small customer who we had to send back to the gate. Everyone holding their own passport is now on their way to California, and we are sorry for the delay."

After arriving in California, some passengers joked about the unusual nature of the delay.

"It's clear the mouse can't enter U.S. airspace without a passport, but in general I think it makes sense," passenger Annina Salven said to the station. "Because I really wouldn't want to eat food on a plane that had a mouse."

But rodents can pose a serious safety risk onboard a plane that goes beyond catering.

The Independent newspaper of London writes “mice have been known to gnaw through wiring on planes, wide-ranging checks must be made to ferret out any problems. A chewed cable could be located anywhere between the tail and the ram air turbine (RAT).”

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