The bailout of Prestwick Airport by the Scottish Government is on course to reach £40m in the next financial year.

The South Ayrshire airport was purchased by the devolved administration for £1 in 2013 after fears its then owner Infratil would close the airport.

It was on the market for 18 months before the Scottish Government purchased the business after no other buyer could be found.

Next year the devolved administration will provide £9.4m of loans to the struggling airport, taking the total amount of taxpayers' money spent on the businesses to £39.5m since 2013.

This means the airport is requiring funding at a faster rate than was estimated at the point of purchase by the Scottish Government.

Government spending watchdog Audit Scotland estimated such a level of funding would not take place until 2021-22.

Repayments will not be made by the airport until it begins operating a profit again. It is currently estimated the business will not return to profit until 2023.

Scottish Conservative MSP Liam Kerr said: "These figures are further evidence that the costs regarding Prestwick Airport are starting to get out of control.

"The amount of public money being sunk into the airport is spiralling and taxpayers are getting increasingly fed up.

"It's time the SNP government got a grip of the situation and started putting plans in place to return the airport to the private sector as soon as possible."

A Scottish Government spokesman said "We have been very clear from the outset that our investment in the airport is on a commercial basis, in the form of loan funding. This attracts a market rate of interest in line with state aid rules.

"A report from Audit Scotland confirmed we are highly likely to generate a return on our investment that is higher than the current rate of interest we are charging the airport.

"We have not set a limit on the overall loan funding we may have to provide to the airport. We plan to approve the amount of loan funding required in any one year through the approval of the airport's business plan for that year."