Mafia clans have used a popular football show on Italian television to send secret messages to jailed godfathers held in isolation, a magistrate has revealed.

Imprisoned crime bosses were kept up to date on mob business through mobile phone texts sent to the show, Quelli Che il Calcio, which unwittingly scrolled them across the bottom of the screen, among innocent messages from supporters of Italian football teams.

Enzo Macri, a magistrate tipped off after a letter advising a jailed boss to watch the show was intercepted, cited one of the texts, "Everything is OK - Paolo," as being sent by a clan affiliate.