The cabinet secretary Simon Case is being sued by a former Treasury official for “discrimination and harassment”.
Rishi Sunak’s top official at No 10 is among those named in an employment tribunal claim, despite efforts to keep him out of the lawsuit.
Rowaa Ahmar said she was subject to “direct discrimination and harassment on the grounds of her sex and race”, lodging a further claim over alleged “victimisation”.
Mr Case and three other Whitehall mandarins, along with the Cabinet Office, have been named in the discrimination claim.
The country’s top civil servant tried to get his name removed from the lawsuit, with his lawyers arguing that there were no “substantive” allegations against him.
Lawyers also argued that two other top officials – Alex Chisholm, permanent secretary in the Cabinet Office, and Sarah Harrison, chief operating officer in the Cabinet Office – should not be named.
Like Mr Case, lawyers argued that officials had played only “minor roles in the issues giving rise to these claims”.
But Judge McGrade, in an interim judgement, turned down the request to remove their names – arguing it could complicate the case.
Ms Ahmar claimed she resigned from her job at the Treasury because of “what she believes to be the failures of all three respondents, which included breaking the rules”.
Mr Case has been under pressure since Matt Hancock’s leaked messages showed him criticising Boris Johnson and mocking holidaymakers forced to isolate during Covid.
Government sources said the cabinet secretary could be forced to quit because more messages are likely to be published during the Covid inquiry which are “utterly indefensible”.
Tory MPs have criticised Mr Case and expressed surprise he managed to avoid fines during the Partygate saga, since he was photographed at some of the rule-breaking events.
But Mr Sunak had praised Mr Case and said he wanted to foster their working relationship. “He works very hard to support me, to support the government’s agenda,” he said last month.
A Cabinet Office spokesperson said: “We do not tolerate bullying, harassment or discrimination and any complaints are taken extremely seriously. There are clear procedures in place to ensure that complaints are handled with sensitivity and fairness.”
They added: “We are defending these claims and cannot comment further on an ongoing employment tribunal.”