Airline passengers have a new incentive to squeeze all their luggage into a single carry-on bag. British Airways is changing its rules for cabin bags, increasing the maximum size by 40% and scrapping the existing 6kg weight limit.

From July 5, all British Airways passengers — whether flying in first class or economy — will be able to carry on one bag measuring up to 56cm x 45cm x 25cm. Until now, all airlines have quoted the maximum dimensions as 55cm x 40cm x 20cm. BA passengers will also be allowed to take on a laptop or briefcase, provided it will slide under the seat.

BA says it wants to encourage passengers to travel light. It is also responding to new security measures: the British Airports Authority has said that from “some time this summer”, it will no longer allow oversized cabin bags through security. Any passenger exceeding the new government-approved limit of 56cm x 45cm x 25cm will be sent back to check-in.

Ryanair allows one carry-on bag weighing up to 10kg. Passengers who check baggage into the hold are charged extra. Flybe also charges to check bags and has a 10kg cabin allowance.

EasyJet has no weight limit on cabin bags as long as passengers can safely lift them into overhead lockers.