World Duty Free, the biggest provider of duty-free shops at UK airports, now requires alcohol to be sold in sealed bags to prevent the contents being accessed before or during a flight.

The change was introduced without announcement at the end of 2018, according to The Times, which reported that airlines have been calling for the measure for several years.

World Duty Free shops are found at most large UK airports, including Bristol, Manchester, Heathrow, Gatwick, Belfast City and Edinburgh.

The new sealed bags require a sharp object to get into and are labelled: ‘Do not open alcohol purchases until your final destination’.

A World Duty Free spokesperson told The Times that while instances of bad behaviour by drunk passengers were rare, “where they do happen, the impact can be serious for fellow passengers, employees working in the air and at the airport.”

“The industry is working together to tackle this problem and make disruptive behaviour such as this socially unacceptable,” the spokesperson said.

“The vast majority of our customers understand that the alcohol we sell can only be consumed when they reach their destination, and this message is already clearly conveyed at tills, on receipts and on bags.”

Last November, the UK government launched a public consultation into airport alcohol licensing laws, saying it wanted to reduce disruption caused by drunk passengers.

Airside pubs, bars, restaurants, lounges and shops at international airports in England and Wales are not subject to the 2003 Licensing Act, which the government said meant they could sell to visible drunk people and promote “irresponsible” deals.

It also cited a 2017 survey by Unite of 4,000 cabin crew working for British-based airlines, which found that 87 per cent of respondents had witnessed drunken passenger behaviour at UK airports or on flights from UK airports.

Travellers can face up to two years in prison or an unlimited fine for drunkenness on an aircraft.