A new system of smart boarding cards is being introduced at Heathrow is an effort to ensure passengers arrive at departures gates on time.

Late-running passengers are responsible for 50,000 minutes of delays a year at Terminals 1, 3 and 4, creating a bill of £3.5 million.

Boarding passes already include a bar code in which the passenger’s flight details are embedded, including the gate and terminal.

Instead of being read by airport staff, the new pass is scanned by an automatic gate and can be used to tell airlines if a passenger has entered the departure lounge, the Daily Telegraph reports.

If the traveller turns up less than 30 minutes before departure — the cut-off time set by airlines to reach the gate — they are sent back to the check-in desk.

The smart boarding pass is also able to redirect passengers to the correct terminal where necessary.

Virgin Atlantic and domestic arm Little Red found that 44% of 35,000 departing passengers in a week of trials at Terminals 1 and 3 were in danger of arriving at the gate late.

About 700 were told to hurry up, and another 10 were instructed to go back to check-in because they had not allowed enough time to clear security.

Offloading luggage because owners have failed to turn up can lead to aircraft losing their take-off slots.

This can lead to delays which, according to industry estimates, cost £67 for each minute the plane is on the tarmac or stuck on the stand, according to the newspaper.

Once a slot is lost, the aircraft has to go to the back of a queue and a 20-minute delay is not uncommon.