EasyJet passengers are being warned that they must turn up for their flights 30 minutes before departure.

The new measure being imposed at Gatwick is designed to ensure flights leave on time.

The budget carrier said that the new rule was being brought in because “punctuality is important to our passengers”.

A spokesman said: “That is why we ask passengers to be at the gate no later than 30 minutes before the flight departs.

“This means that if passengers are still to clear security they will be unable to achieve this, particularly at larger airports like Gatwick when walks to some gates can take up to 20 minutes.

“We are implementing this … to eliminate unnecessary journeys for passengers. The vast majority of our passengers arrive as we suggest at the gate before 30 [minutes] to board the aircraft.”

Gatwick, from where EasyJet operates 60 aircraft, was ranked 192nd out of 196 of the world’s airports for punctuality, according to aviation data firm OAG.

About 79% of EasyJet flights arrived on time or within 15 minutes of their scheduled arrival time in March, latest figures from the airline suggest, compared with 86% during the same month last year.

The move will affect 15 million EasyJet passengers who fly from Gatwick each year.

Those who arrive late can either abandon their journey or pay £80 to take an alternative flight.

The Times reported that travellers will be warned of the change by a note on their boarding pass, saying: “Gatwick security control gates are automatically being timed to close 30 minutes before departure.”

Rejected customers will be told to go to the desk “to rearrange their travel arrangements”.