David Cameron’s bodyguard has been taken off frontline duties after reportedly leaving his gun and the former prime minister’s passport in an aeroplane toilet.

A passenger found the weapon and handed it to flight attendants on the British Airways flight, the Daily Mail reported.

The gun, believed to be a 9mm Glock 17 pistol, was said to have been left by a close-protection officer who took off his holster while using the toilet.

The former prime minister’s passport was found alongside the officer’s, according to The Sun.

“The captain confirmed a gun had been found, which freaked everyone out,” the paper quoted one of the passengers as saying.

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The captain attempted to reassure passengers by telling them the protection officer was authorised to bring a gun on board.

He said the weapon had been returned, but several passengers objected and the gun was removed before take-off.

The flight, from New York to London, was delayed by over an hour.

An unnamed 33-year-old businessman told The Sun: “There was a real commotion going on with a guy near to me. He said he had found a gun in the toilets, which was met with disbelief.

“A few minutes later the captain came into our section and confirmed a gun had been found — which freaked everyone out.

“He tried to calm everyone down by explaining that the law allowed handguns on planes for protection officers and that the gun was back with the bodyguard.

‘But a guy wasn’t having it. He said he felt uncomfortable about guns being allowed on the plane.

“’The captain left and came back a few minutes later to say the gun had been removed from the plane.”

Another passenger told the Mail: “A guy started to show pictures on his phone of a gun and two passports – one was David Cameron’s – he said he found in the toilet.

“They were just resting on the side by the sink. He was stunned by what he saw.

“Later the man pointed out the bodyguard as he came through our section. He was dressed casually, which surprised me, in jeans and a black and grey striped top.”

In a statement, the Metropolitan Police said: “We are aware of the incident on a flight into the UK on 3 February and the officer involved has since been removed from operational duties.

“We are taking this matter extremely seriously and an internal investigation is taking place.”

British Airways said it followed Civil Aviation Authority rules which allow UK police to carry firearms on board in specific, controlled circumstances.

“Our crew dealt with the issue quickly before departure and the flight continued as normal,” the airline said.