British authorities have revealed that a man who had called for the assassination of Prince George has been stabbed in prison, without any information available on who stabbed him and what the motives were.

The Daily Star said Saturday that Husnain Rashid, who had been jailed earlier this month for offering advices to supporters on how to kill the young member of the British royal family, was found in his cell in Manchester’s Strangeways jail while having his face slashed with a makeshift knife.

Rashid’s body was discovered in the early hours of Wednesday with a huge gash from his right ear while blood was everywhere around the cell.

He was stabbed with a toothbrush that had a blade attached to it, authorities said, without elaborating how the attack happened and who was behind it.

A source in the prison claimed Rashid was disliked by other inmates, saying that everyone wanted to kill him due to his threats on the five-year-old Prince George.

“We don’t tolerate that kind of thing in Strangeways,” said the source, adding, “Nobody likes him or what he did, like threatening that young royal lad...”

Britain's Princess Charlotte of Cambridge and Britain's Prince George of Cambridge hold hands with their father, Britain's Prince William, Duke of Cambridge, at the Chapel Royal, St James's Palace, London on July 9, 2018. (AFP photo)

Prison authorities said they had launched an investigation, without offering other details.

Authorities had earlier linked Rashid, 32, to the Daesh (ISIL) terrorist group. However, there was no clear evidence suggesting the man was a terrorist other than his phone calls with a friend in Syria, which has yet to be verified.

The unemployed web designer from Nelson, Lancashire, was given 25 years behind bars for encouraging supporters to kill George, the oldest child of Prince William and his wife, Kate.

Rashid used Telegram, a messenger application to communicate with his supporters until he was arrested on November 22 last year. He has openly admitted to the charge.

Anti-monarchy sentiments have been on rise in Britain over the past years, especially among the poor youth who are irked by the luxurious lifestyle of the Royal Family.