The private physician to Princess Diana, who also identified her dead body following a fatal Paris car crash in 1997, is being sued by the widow of a top City banker.

Dr Peter Wheeler, who is known to have treated celebrities including Nigella Lawson, alongside Prince Charles and the Duke of Kent, is facing damages worth £300,000 in connection with the death of Stefanos Vavalidis, a senior director at the National Bank of Greece.

Vavalidis' widow Barbara alleges that her husband's death from liver cancer in January 2016, aged 69, was hastened by Wheeler's negligent prescription of methotrexate. She is now suing the doctor in the High Court.

According to the writ, the drug was originally given to Vavalidis between May 2003 and 2015 to treat the skin condition psoriasis, but ultimately worsened the banker's liver and damaged his overall health, causing him to "suffer gravely".

It is further stated that his condition deteriorated so much that the couple considered moving from their four-storey townhouse in Chelsea to a flat with a lift.

Legal representatives for Barbara, Leigh Day, allege her husband would become breathless when walking, potentially as a result of lung fibrosis.

This is stated as the reason for his health continuing to decline while on a family holiday in May 2015, during which a local doctor allegedly said his immune system was shutting down.

Months later Vivalidis was flown to University College Hospital in London, where he died of cirrhosis of the liver, with pneumonia and renal infection, reported The Telegraph.

Importance of methotrexate

According to Barbara, the toxicity of the methotrexate was to blame for her husband's death.

The writ alleges that Wheeler "knew, or ought to have known, that methotrexate is a high-risk drug with potentially serious side effects that can be fatal if it is not used correctly".

Barbara is seeking damages for herself and two sons Alexander, 32, and Philip, 27. She believes that her husband would still be alive if he had stopped taking methotrexate.

Wheeler, a partner at the Sloane Street Surgery, in Knightsbridge, west London, is expected to deny the allegations, but had not responded to a request for comment at the time of writing.