In legal papers, seen by BBC News, Dr Susan Gilby alleges she was effectively unfairly dismissed by the Countess of Chester NHS Foundation Trust, after she made a formal complaint.

She has also accused the chairman of putting finance above patient safety.

In a statement, the trust said it denied all the allegations.

Dr Gilby, a consultant in anaesthesia and intensive care, was appointed as medical director and assistant chief executive of the NHS trust, in August 2018.

Her arrival came a month after nurse Lucy Letby was arrested on suspicion of murdering seven babies and attempting to kill 10 others at one of the trust's hospitals in Cheshire. Ms Letby's trial is ongoing and she denies the charges.

When the chief executive resigned in September that year, Dr Gilby was promoted to the role.

According to documents prepared for a forthcoming employment tribunal, Dr Gilby alleges the problems began when a new chairman, Ian Haythornthwaite, was appointed in late 2021.

She claims that soon after joining the trust, Mr Haythornthwaite - a former BBC accountant - sought to "intervene and influence, and ultimately to control, many operational matters" beyond the scope of his job.

Dr Gilby's claim alleges that the chairman had an "extremely and unnecessarily aggressive" approach, with subordinates "increasingly frightened of crossing him".

She also accuses him of appointing friends to the trust's board and putting finance above patient safety.

Dr Gilby claims the chairman was "highly aggressive and intimidatory" in meetings, that he banged his hand on a desk to emphasise his point, and oversaw a climate where "offensively sexist comments and ferocious and repetitive criticisms" were made by either him or his associates.

Dr Gilby's complaint accuses the chairman of putting finance above patient safety at the hospital trust

She made a formal whistle-blowing complaint against the chairman in July 2022, raising her concerns about his behaviour to both the trust and NHS England.

The trust responded to her concerns, Dr Gilby claims, by proposing that she be seconded to a senior advisory role within NHS England on the condition she withdrew her allegations.

NHS England also contacted her about a role. Dr Gilby responded to the offer in November saying she was not willing to withdraw her allegations; she was suspended by the trust on 2 December. On 5 December, she gave the trust six months' notice of her intention to resign.

Dr Gilby is suing the trust and Mr Haythornthwaite for constructive unfair dismissal.

In a statement, the Countess of Chester NHS Trust said: "There are significant points of dispute between Dr Gilby and the trust and the trust denies all allegations that she has raised. A number of active internal investigations are in train and the trust will not provide any further comment whilst those investigations are ongoing."

Mr Haythornthwaite said he had "nothing to add at this time" to the trust's statement.