A stash of cocaine valued at £100,000 was discovered hidden in a toilet on a British Airways plane by a maintenance engineer at Gatwick Airport.

The package was noticed behind a panel while the Boeing aircraft was undergoing standard inspections in a hangar.

The drugs were found after the flight arrived from Orlando, Florida.

The engineer called police and now Border Force officials and the National Crime Agency are investigating.

Last night, a source said: “This is an astonishing find — and a serious security breach.

“Someone has smuggled it on to the flight so it’s very worrying, and it could potentially have been a more dangerous substance.

“They were hoping to pick it up and recover it in the UK but were undone when the flight went for its service.

“The block had been well hidden for someone to retrieve later.

“Whoever it was got unlucky, because the plane was taken into a hangar for a check-over, like a car’s MoT.

“That’s when the find was made — and it was in a panel behind a bin in the toilet.

“It’s quite likely to have been hidden there by a member of staff of some sort — either a fight attendant or baggage handler or cleaner.

“It’s unlikely to have been a member of the public because they would not have been able to get on the plane to pick it up later.

“Whoever it is, I wouldn’t want to be in their shoes now as they’ve lost something of value to criminals.”

British Airways did not comment because of the police investigation.

But a government spokesperson said: “Those who attempt to smuggle illegal drugs into the UK should be in no doubt Border Force will find them.”