Low-cost long-haul carrier AirAsia X reported a “challenging year” and a 15% fall in passenger numbers on 2014 as it published annual results for 2015.

A subsidiary of Asian regional low-cost carrier AirAsia, based in Kuala Lumpur, the airline cut capacity by 6% on 2014 over the year but still saw a decline of seven percentage points in average load factor to 75%.

AirAsia X reduced capacity by 10% in the final three months of the year despite adding an aircraft to its fleet of Airbus A330s and saw a 9% reduction in passengers over the quarter compared with the previous year.

In a statement the carrier described 2015 as “challenging”, reporting: “The group was set back by irrational competition from industry peers, currency volatility [and] regulatory uncertainties, as well as a series of unforeseen circumstances.”

The carrier ceased flying to Adelaide, to Toyko Narita and to Nagoya in Japan last year.

AirAsia X formerly flew between London Gatwick and Kuala Lumpur but withdrew from the route in 2012 when it also ceased flights to Paris.

The carrier launched to London Stansted in 2009 and switched to Gatwick in late 2011, months before pulling out of Europe.

AirAsia group chief executive Tony Fernandes, who is also chairman of London football club Queens Park Rangers, suggested in late 2014 that a return of London-Kuala Lumpur services could be imminent. The latest results appear to make this unlikely.