An alleged Italian mafia boss who was arrested in London last month after two decades on the run will appear via video link for a bail hearing on Friday.

Italy wants to extradite Domenico Rancadore, 64, so that he can serve a seven-year jail term for his role in the Sicilian mafia. Known in the mafia as "The Professor", he had been on Rome's list of most dangerous criminals.

He has already twice been denied bail, and will make his latest bid at Westminster Magistrates' Court in London later Friday.

At an earlier hearing, prosecutor Aaron Watkins argued there were "overwhelming grounds" to suspect that he would go on the run again if granted bail.

Rancadore had been living in a modest suburban house in west London under the name of Marc Skinner, with his English wife and children, when he was arrested on August 8.

He told British officers upon his arrest that he was not going back to Italy because "they will kill me."