John Ross, 46, was less than two weeks into a three-month sentence for ramming a table into the nurse's stomach.

Edinburgh Sheriff Court was told that he attacked the woman because he was "having a bad day" after a taxi was late picking him up.

Sources at Edinburgh's Saughton prison said Ross's death was due to natural causes.

Prosecutors said Ross would have been able to see that Eunice Kudom, a staff nurse, was almost six months pregnant at the time. But he screamed a volley of racist abuse at the Afro-Caribbean health worker, who was helping him to have kidney dialysis.

Graham Fraser, the fiscal depute, told the court last month how Ms Kudom, 28, had telephoned Ross after he failed to turn up for an appointment at Edinburgh Royal Infirmary. She was due to help him with kidney dialysis, which he needs three times every week.

A spokesman for the Scottish Prison Service said: "Police and next of kin have now been informed and a Fatal Accident Inquiry will be held."