The figure was included in a new annual report that showed the airport’s losses increased from £3.9 million in 2013/2014 to £4.1 million in 2014/15, raising questions about its long-term future.

The airport was taken into public ownership in late 2013 in order to secure up to 3,200 jobs at the airport.

In February, an Audit Scotland report said it was “highly likely that the Scottish Government’s return on its investment over the 30-year period would still be more than the interest rate of 3.24 per cent currently charged to the airport on the loan funding”.

A spokesperson for the Scottish Government echoed the sentiment, saying: “These financial results are as we expected. As we made clear at the start of the acquisition process, this is a long-term investment.

“There is no quick fix to turn Glasgow Prestwick Airport around but there are real opportunities to improve in all areas of the business.”

The airport’s chief executive Iain Cochrane added: “Following another challenging year, the airport continues to work to turn around the financial performance and there are promising signs in a number of areas, though growing the passenger business remains a challenge whilst air passenger duty exists at its current level.

“The airport is a frontrunner in the process to become the first designated UK spaceport and is continually looking for opportunities to maximise both income and the broad scope and opportunity offered as a strategic national asset.”