Doncaster Sheffield Airport is set to close, just two weeks after Liz Truss promised to "protect it".
On Monday, the owner of Doncaster Sheffield Airport (DSA), the Peel Group, said a strategic review had concluded the airport was "not viable due to its lack of adequate forward revenues and high operating costs".
The airport is thought to employ more than 800 people, with a further 2,700 jobs affected in the supply chain.
The chairman of Peel Airports Group, Robert Hough, said in a statement: "We recognise that this will come as a great disappointment to many. The intractable problem remains the fundamental and insufficient lack of current or prospective revenue streams, together with the airport’s high operating costs.
The announcement could make uncomfortable reading for Truss, who was asked about the airport during her first prime minister's questions on 7 September.
Quizzed about the airport's future by Don Valley MP Nick Fletcher, Truss told Parliament: “We will protect this airport and this infrastructure”.
She said that she had already instructed Anne-Marie Trevelyan, her new transport secretary, to begin talks with stakeholders.
She said at the time: "I will as PM be absolutely focusing on levelling up and making sure we’re attracting investment and growth into this country that have been left behind so they have their share."
But the promise appears to have been short-lived, and now up to 3,500 jobs are at risk as the airport begins to "wind down" from the end of October.
Watch: How will the plunge of the pound affect the cost of living crisis?
The news is the latest in a line of uncomfortable events since Truss won the Tory leadership contest at the start of September.
Some Tory MPs have reportedly already begun talking about handing in letters of no confidence, fearing the new PM could crash the UK economy as it endures a cost of living crisis.
New chancellor Kwasi Kwarteng delivered his 'mini-budget' of tax cuts on Friday which saw the value of the pound tank.
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Sterling dropped to its lowest level against the dollar since decimalisation in 1971 following Kwarteng's announcement, falling more than 4 per cent. It regained some ground to a 20-year low of $1.05 before recovering further to $1.075 just after 10am on Monday.
However, one ex-minister from Boris Johnson's government told Sky News: “Liz is f*****. She is taking on markets and the Bank of England." He added that Truss and her Treasury ministers were “playing A-level economics with people’s lives”.
Tory support continued to wane last week according to political polling body Redfield and Wilton.
The group found that were a general election to take place now. Labour would hold a 10% lead over the Conservatives.