According to reports, Stewart claims she was fired just as she was about to reveal details of the financial crisis facing Gordon Ramsay Holdings’ restaurants.
If successful in her claim, Stewart could be awarded up to £80,400 – the maximum compensation and basic pay for a “normal” unfair dismissal case.
A spokesperson for GRH said: “There is a legal process underway and it would be inappropriate for us to comment on the detail of this action, other than to say we dispute the claims and will be defending our position.”
Her departure from the company, and subsequent claim, comes just months after Ramsay’s father-in-law and business partner Chris Hutcheson left the business following an argument with the celebrity chef.
Upon his departure the group confirmed that Hutcheson would remain a shareholder, although after a tussle over the fate of Mayfair restaurant Petrus, it is unclear what his stake is now.
Stewart was director of Gordon Ramsay Interactive and had a 2.5 per cent share of GRH.