Yvan Colonna, 61, who had been serving a life sentence for murdering a local official, was beaten by another inmate, a Cameroonian jihadist, on 2 March.

The attack left Colonna in a coma and he was receiving treatment in a hospital in the south of France.

The assault provoked riots in Corsica, where many saw him as a hero in its campaign for independence from France.

Colonna was jailed twenty years ago for shooting dead Corsica's top official in 1998, following a five-year manhunt that eventually found him in the mountains living as a shepherd.

According to prosecutors, he was working out in the prison gym when Franck Elong Abé, 35, a former jihadist serving time for terror offences, allegedly launched his attack.

Abé tried to suffocate Colonna with a bin bag after hearing him "blaspheming" and mocking the prophet Muhammed, investigators say.