The new CT scanners mean passengers travelling through all four terminals at the UK's hub airport will no longer need to remove liquids or electronics from their hand luggage.

Heathrow said the upgrade would speed up transit through security, reduce stress for passengers and drastically cut plastic waste.

CT scanners provide better images of cabin baggage, allowing security to process more passengers – "thousands" – per hour. The airport also estimates the move will reduce plastic bag usage by almost 16 million a year.

Last year, more than 97% of passengers departing Heathrow cleared security in less than five minutes.

Thomas Woldbye, Heathrow's chief executive, said: “Every Heathrow passenger can now leave their liquids and laptops in their bags at security as we become the largest airport in the world to roll out the latest security scanning technology. That means less time preparing for security and more time enjoying their journey – and millions fewer single-use plastic bags.

"This billion-pound investment means our customers can be confident they will continue to have a great experience at Heathrow."