Last year, Tui’s airline emissions fell 2.3% following a fleet replacement programme that, the company says, means airline is now the most climate-efficient in Europe.

Thomson Airways ranked second last year in the Atmosfair Airline Index of medium and long-haul airlines, while Tuifly in Germany was ranked the world’s most climate-efficient airline for the third consecutive time.

In the group’s hotel sector, 68% of TUI’s properties had a sustainability certificate recognised by the Global Sustainable Tourism Council in 2015, while more than 500,000 guests took a TUI Collection excursion tailored to promote sustainability.

Fritz Joussen, Tui Group chief executive, said the first year of the project had made considerable progress.

“For us, environmental and social sustainability are two sides of the same coin. Our ambitious sustainability strategy, ‘Better Holiday, Better World 2015-2020’, illustrates the depth of our engagement.

“The progress achieved in the first year of our strategy has been encouraging. We are determined to maintain momentum and to continue to invest in opportunities that tourism offers to people worldwide.”