A private hospital's failure to provide preventative medication contributed to the death of Lady Joan Branson, an inquest has concluded.

The 80-year-old, who was married to Sir Richard Branson, died on 24 November last year after suffering a cardiac arrest at the private Lister Hospital in Chelsea, west London.

Senior coroner Professor Fiona Wilcox told Westminster Coroner's Court on Wednesday that Lady Joan did not receive prophylactic anticoagulants at the hospital despite a "very high risk of developing deep vein thrombosis".

"I do find her death would likely have been prevented, and the lack of anticoagulation did cause or contribute to her death probably," she said.

The coroner's court heard that Lady Joan was admitted to the hospital on 17 November after a fall weeks earlier on Necker Island, a British Virgin Island owned by her billionaire husband.

She died after suffering a pulmonary embolism, a sudden, dangerous blockage in a lung artery, resulting from deep vein thrombosis.

Haematologist Dr George Adams told the inquest that Lady Joan was "extremely high risk" for blood clots and the "biggest risk factor by far was her immobility and her fracture".

From her hospital admission to her death, Glasgow-born Lady Joan did not receive any prophylactic anticoagulation, which is used to stop blood clots from forming.

The hospital's admitting doctor, Dr Basir Kunduzi, did not complete a bleeding risk assessment on the day of her admission, the inquest heard.

Dr Kunduzi said Lady Joan's death led him to "reflect on my role as a doctor" and the importance of "good communication between team members".

Giving her conclusion, Professor Wilcox said it was "not a case of neglect" and there "wasn't an absence of treatment".

After her death, Sir Richard described his wife as the "shining star around which our family's universe has always orbited".