In the latest warning from the government about the dangers of a Brexit, the Treasury pointed out that low cost air fares have fallen by more than 40% between 1992 and 2000, following the introduction of a single market for aviation which allows any EU airline to operate routes from and between any EU airport.

But it said outside the single market, the UK would lose this benefit which has increased competition and driven down costs for passengers.

Carolyn McCall, chief executive of easyJet said: “For easyJet and our passengers membership of the EU has been a good thing. The common aviation area created by the EU allows any European airline to fly anywhere in Europe. This has kept all airlines’ costs low and has enabled low fares airlines like easyJet to expand.

“If the UK were to vote to leave the EU any new, more restrictive aviation arrangements would add cost and therefore fares would rise.”

Roaming costs

The Treasury also warned cheaper overseas roaming charges would be under threat in the event of a ‘leave’ vote.

The cost of mobile phone roaming charges has already been cut to nearly zero in Europe and from June 2017, all roaming charges across the EU will be completely abolished.

“These arrangements, which benefit millions of British travellers every year, would not be guaranteed to continue were the UK to leave the European Union,” the Treasury said.

Gavin Patterson, chief executive of BT Group, which owns EE, said: “Because of the UK’s membership of the EU, BT and EE have been able to offer our customers lower charges, including inclusive roaming plans and data charges that are over 90% lower for Britons travelling on the continent.

“Voters need to think very carefully before turning their backs on an institution that helps to ensure benefits like that are delivered.”

Holiday prices

The latest Treasury analysis also estimated the value of the pound will fall by 12% immediately following a vote to leave, making travel in Europe and the rest of the world more expensive.

On average, after two years, a four-person holiday travelling together would spend £230 more during an eight-night holiday in Europe, it said.

The Treasury warned the fall in the value of the pound would affect all holiday expenditure abroad that is paid for after a vote to leave the EU on 23 June.