The boss of easyJet has said it is “absolutely legal” to travel to amber list countries and has criticised the “very confusing” messages from the UK government about the traffic light system that came into effect on Monday.

Speaking after the budget carrier revealed a £701 million loss for the six months to the end of March, chief executive Johan Lundgren said the whole point of the traffic light system was to allow travel to safely restart. He added that health data proves most European countries should be on the green list, which currently includes just 12 destinations, not all of which are accepting foreign visitors.

“There are no indications [passengers] shouldn’t travel to these [amber list] countries, because that’s what the restriction was supposed to do – it was there to make sure you could do this in a safe way,” Mr Lundgren said.

“We have a huge amount of people who are contacting us to say: ‘Look, can I go? Can’t I go?’ So it’s been very confusing, and the government is almost dismantling the system that it set up themselves.”

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Based on current restrictions, easyJet expects to fly only about 15 per cent of its 2019 capacity during the three months to the end of June, down from the 20% it had previously indicated. However, there is “significant flexibility” to ramp capacity up or down, with capacity levels expected to start increasing from June onwards.

Mr Lundgren said the airline added more than 105,000 seats after the green list countries were announced, and has the ability to quickly get 90% of its fleet in operation over the peak summer period. With the EU having provisionally agreed earlier this week to ease travel restrictions for vaccinated people, easyJet and others within the industry are pushing for more countries to be added to the UK’s green list.

Mr Lundgren specifically cited Greece and Spain, but added that “the majority of countries in Europe should be on the green list”.

His comments came after London-listed group posted its financial results for the first half of the year, which showed a hefty increase on the losses typically incurred during the winter months. Passenger numbers during the six months to March 31 plunged by nearly 90% to 4.1 million, with capacity down by 85% to 6.4 million seats.

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Revenues crashed from £2.4 billion to just £240m, with the pre-tax loss widening to £701m against a loss of £193m in the same period a year earlier.

EasyJet highlighted its “robust” balance sheet, which has been strengthened to the tune of £5.5bn of liquidity raised through the course of the pandemic. This included a £450m rights issue launched in June of last year.

Net debt at the end of March stood at £2bn, up from £467m a year earlier. Analysts David Kimberley of Freetrade said this will be a concern going forward.

“Regular travel should mean the company can get back to its pre-pandemic profitability, and if European vaccine rollouts speed up, then the firm will be better-placed than some to start taking people abroad,” he said. “But the problem for shareholders now becomes the mound of debt the firm has built up during the past 12 months.

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“EasyJet has close to seven times as much debt as it did prior to the pandemic and that will undoubtedly eat into future earnings. That’s on top of last year’s share placing which, representing close to 20% of the company’s free float, also meant a substantial dilution of shareholder value.

“So even if the more immediate damage the pandemic has caused may soon be over, there are going to be long-lasting consequences that the airline will have to struggle with for years to come.”

To help mitigate some of the financial toll of Covid, easyJet has implemented a cost-cutting programme that aims to deliver £500m in savings this year.