Full-year operating profit (to December 31, 2017) was just over €3 billion before exceptional items, up 18.9% compared to the previous year.

However quarterly profits slipped from €620 million to €585 million.

Total revenues for the year climbed 1.8 per cent to €23 billion, while pre-tax profits climbed 5.5% to €2.5 billion.

Passenger unit revenue for the year was down 1%, but up 1.5% at constant currency.

Willie Walsh, IAG chief executive officer, said: “All our airlines performed extremely well with their best-ever individual financial results, strong operational performances and commitment to customer service. The turnaround in Vueling, following the challenges of 2016, has been particularly outstanding.

“In Quarter 4 we reported an operating profit of €585 million, down from €620 million last year. Our strong performance continued with passenger unit revenue up 2.4% at constant currency. The operating profit was impacted significantly by changes in the employee bonus provision in the quarter compared to the previous year.

“Our confidence in IAG’s future remains undaunted.”

IAG announced a share buyback of €500 million during 2018.

At current fuel prices and exchange rates, the firm expects its operating profit for 2018 to show an increase year-on-year. Both passenger unit revenue and non-fuel unit costs are expected to improve at constant currency.