An airline pilot due to fly over 260 passengers from London to Hong Kong has been arrested at Heathrow Airport after he was allegedly found to be in possession of a number of knives.
A spokesperson for the airline Cathay Pacific said that the flight - which was due to travel from London Heathrow to Hong Kong at 10:20pm on Saturday - was delayed following a "crew-related incident".
The Metropolitan Police said they were called to a staff search area at Heathrow at around 9:10pm on Saturday and found a member of the flight crew in possession of "some knives."
A Met police spokesman said: "Officers attended and subsequently a member of the flight crew, a man, was arrested on suspicion of possession of an offensive weapon in a public place and possession of knife blade / sharp pointed article in a public place.
"He was taken into custody at a local police station where he was later bailed to return in mid-May pending further inquiries. The CID at Heathrow airport is investigating." The man, who is believed to be 61, was taken to a local police station and has been bailed until next month.
The airline said that: "At no point were passengers or staff put at risk. Given timings, Cathay Pacific were unable to organise a relief crew and therefore passengers experienced an overnight delay.
"Cathay Pacific takes this very seriously and is liaising with the relevant authorities. The airline assisted passengers with overnight accommodation and alternative flight arrangements."
Meanwhile, in the US United Airlines banned a security researcher from a flight after he tweeted that he might be able to hack the aircraft's systems.
Chris Roberts was due to fly from Colorado to San Francisco to talk at a major security conference on Saturday. Earlier, he tweeted he thought he could deploy the oxygen masks on board. Despite the ban, United said: "We are confident our flight control systems could not be accessed through techniques [Mr Roberts] described."
Mr Roberts is the founder of a cybersecurity firm, One World Labs, that tries to find vulnerabilities in IT systems and alert companies to them before they are exploited by criminals.
Last week Mr Roberts was removed from another United flight by the FBI who took his laptop away, and questioned him for four hours. As part of his job, Mr Roberts had given several interviews to the media in recent weeks in which he commented on the possible weak points of airline systems.
He told Fox News: "Quite simply put, we can theorise on how to turn the engines off at 35,000ft and not have any of those damn flashing lights go off in the cockpit."
He also told CNN that he could connect to a computer under his seat to view data from the aircraft's engines, fuel and flight-management systems.
Asked why United had prevented Mr Roberts from taking his flight, spokesman Rahsaan Johnson said: "Given Mr Roberts's claims regarding manipulating aircraft systems, we've decided it's in the best interest of our customers and crew members that he not be allowed to fly United.
"However, we are confident our flight control systems could not be accessed through techniques he described."
"We made this decision because Mr Roberts has made comments about having tampered with aircraft equipment, which is a violation of United policy and something customers and crews shouldn't have to deal with."
United said it would send a letter to Mr Roberts to explain its decision within the next two weeks.
The Electronic Frontier Foundation, which campaigns for greater openness and transparency online and represents Mr Roberts, said: "It is disappointing that United refused to allow him to board, and we hope that United learns that computer security researchers are a vital ally, not a threat."