Yorgen Fenech has filed a constitutional case against the State, alleging that his fundamental right to a fair trial was breached through the use of eavesdropping measures, including the alleged installation of a listening device in a prison meeting room where he consulted with his lawyers.

Fenech, who is awaiting trial over the murder of journalist Daphne Caruana Galizia, filed the constitutional challenge on Thursday.

In the claim, Fenech alleges that he was subjected to unlawful surveillance and refers to two warrants approved in 2019.

According to the application, the Security Service authorised the installation of an eavesdropping device in the room at Corradino Correctional Facility where inmates meet with their lawyers.

Fenech is also claiming that two mobile phone numbers were intercepted by the authorities, one of which he said was used to communicate with his legal representatives.

The application states that one of his lawyers, Charles Mercieca, "coincidentally" discovered the first 2019 warrant relating to the alleged listening device in the Corradino meeting room.

Fenech claimed the device remained in place throughout the period between his arrest and his release on bail in 2025.

Through his lawyers, Fenech argued that the alleged surveillance violated his fundamental right to a fair trial.

Earlier this week, the Chamber of Advocates said it was in possession of testimony given behind closed doors indicating that listening devices had been installed in prison rooms used for meetings between inmates and visitors.

The claims prompted the Security Service to issue a rare public statement denying allegations that it recorded conversations between lawyers and their clients inside prison.