Aer Lingus passengers travelling from the Republic of Ireland to the United Kingdom will have to carry a passport under tighter regulations being introduced this month.
It means documents such driving licences or Garda age cards will no longer be accepted for boarding.
From February 25th, all Irish nationals must have a passport to travel to the UK on Aer Lingus flights despite the long-standing Common Travel Area (CTA) arrangement, the airline said.
In addition, all non-Irish nationals travelling to Britain must obtain an Electronic Travel Authorisation (ETA) in advance at a cost of £16 (€18) per person.
The ETA for non-Irish nationals travelling from Ireland to Britain is required by the British government, which has been rolling out the system to different countries over the last few years.
The passport requirement for Irish nationals has been introduced by Aer Lingus, which up to now has accepted other forms of identification such as a driving licence.
Ryanair has imposed the passport requirement for many years, however, arguing the CTA is based on a memorandum of understanding between Ireland and Britain rather than legislation.
Aer Lingus said the new measures “will ensure consistency across our network and further improve our operational performance for our customers”.
Passengers on domestic routes such as Belfast to Britain and Dublin to Donegal will be exempt.
The airline has set up dedicated phone lines for passengers who do not have a passport but need to fly to Britain – or who are in Britain but need to return to Ireland – before they can obtain a passport.
But it said: “If you cannot present a passport/Irish passport card, you won’t be able to travel. Aer Lingus cannot make exceptions to travel document requirements.
“Aer Lingus customer care team will offer customers the best option to suit their individual circumstances, including a refund, a refund voucher or a rebooking to travel at a later date.”