The discovery of a mouse on board led to the cancellation of a British Airways flight from Heathrow to San Francisco yesterday, passengers reported via social media.

The crew told passengers that aircraft cannot take off with mice on board, and that another flight would be scheduled.

But they faced a delay of four hours before eventually taking off on a replacement Boeing 777 about four hours later.

British Airways told the BBC: “We know almost everyone wants to fly with us to San Francisco, but on this occasion there was one very small customer who we had to send back to the gate.

“Everyone with two legs is now on their way to California, and we are sorry for the delay.”

Marius Fermi, UK marketing manager at flight delay claims compensation company AirHelp, suggested that the airline could face a six figure claim for compensation.

He said: “While the presence of a mouse on board is not a typical cause for flight cancellations, under EC261 regulations, British Airways could now owe up to £153,746 in compensation charges to passengers if the Boeing 777 was at full capacity and if the cause of the delay is not deemed as an ‘extraordinary circumstance.

“In this instance, it’s more than likely that the passengers affected will be owed compensation, as previous flight disruptions similar to this have not been deemed ‘extraordinary’ in the past.

“Every year, more than eight million passengers are entitled to flight disruption compensation from airlines, yet only one per cent of eligible passengers will receive the money that they are entitled to.”