Monarch was able to renew its Atol in October 2016 after the airline received £165 million in new funding from its owner Greybull Capital.

But instead of all of this money coming from Greybull, The Sunday Times has revealed that Boeing supported Monarch by pumping £100 million into the airline through an offshore holding company Petrol Jersey.

Boeing’s payments, which were supplied over several months, came through a complicated “sale and leaseback” finance deal related to Monarch’s order for 45 B737 Max airlines from the US aircraft manufacturer.

Monarch secured a “paper” profit through this deal because it was paying less than the market price for the aircraft, and Greybull was able to persuade Boeing to make the £100 million payments to support the airline.

Monarch went into administration on October 9 grounding all flights and forcing the CAA to launch a repatriation programme of flights to bring 110,000 holidaymakers back to the UK at an estimated cost of £60 million.

Both Boeing and Greybull have yet to comment on the deal.