In the letter, Saab’s UK boss Andrew Walton said the company’s UK expansion was based on the “expectation” that MoD “procurement methods and decision will reflect the Government’s commitment to fair and transparent free-market competition”.

He said the company had got permission from the Swedish government to share classified data on Erieye with UK defence officials so they could assess it, but claimed this offer was not taken up.

In the letter, published alongside Defence Secretary Gavin Williamson’s appearance before the committee last week, Mr Walton questioned whether MoD had looked at alternative’s to Boeing.

“We cannot support the assertion Erieye’s performance has been analysed,” Mr Walton wrote. “Without examining classified data it is impossible to understand and judge the performance of the system.”

While Boeing has not built a Wedgetail for five years, Saab said that its system is at the “leading edge of technology” and questioned if there was another reason for picking the US company’s product.

“If unstated political reasons exist for a non-competitive approach to replacing the AWACS then we would be grateful if this could be indicated to us and we will cease marketing in the UK,” Mr Walton wrote.

“Notwithstanding any unknown political factors, we are concerned by the lack of competition and the lack of dialogue and response from the MoD.”