Josie Stewart, a former senior official of the Foreign, Commonwealth and Development Office, was sacked after providing the BBC with anonymous comments criticizing the government’s handling of the Afghanistan withdrawal in 2021.

She launched a legal challenge over the sacking, taking her case to an employment tribunal in an attempt to test the legal protection of whistleblowers in Britain.

However, the government is seeking to hold the case in private based on national security concerns, with Stewart and her lawyers earlier this week attending a preliminary hearing to decide the status of the legal challenge, set for September.

Stewart, using the CrowdJustice website that crowdfunds legal action, said: “This hearing was listed in order to hear and decide upon (the) government’s rule 94 (national security proceedings) application.

“As the hearing was held in private, frustratingly I am not able to share anything that was said. A Guardian reporter whom I met at reception (and) who had turned up to cover the hearing, was turned away.

“What I can say is that we will receive the judge’s decision and reasons on May 18. Also, that I found today intense, emotional, infuriating and motivating. And that my legal team are truly incredible: It was a privilege to witness them at work.

“There are truly important issues at stake, which my lawyers are fighting not only on my behalf. They deserve my and our support.”

Legal sources told The Guardian that the government was attempting to use rule 94 to curtail media coverage of the case over fears that Stewart’s commentary could embarrass the FCDO.

The former official has said that her seven years at the FCDO was spent, together with colleagues, protecting ministers who wanted to “look good.”

Stewart now works for the anti-corruption nonprofit Transparency International.

She told The Guardian earlier this year: “If the law is not tested and used then I don’t know how much it actually means, as potential whistleblowers don’t know which side of the line it is going to fall.

“Is what they’re going to do likely to be legally protected or not? If they don’t know then I’m not sure how meaningful the fact the law exists is.”

In response to the latest developments in the case, an FCDO spokesperson said: “We are rightly proud of our staff who worked tirelessly to evacuate more than 15,000 people from Afghanistan within a fortnight.

“This was the biggest mission of its kind in generations and the second-largest evacuation carried out by any country.”