Former Prime Minister Jean-Claude Juncker testified in court in the ongoing SREL spy scandal affair on Wednesday.

Juncker was called to stand as a witness in front of a full courthouse at the second session of the ongoing trial against three former operatives of the Luxembourg Government State Intelligence Service (SREL). The trial, which had been delayed due to Juncker's aneurysm surgery in November, began on Tuesday.

During his deposition, which lasted 35 minutes, Juncker expressed his 'firm support' of the decision to record Loris Mariotto due to the rumour that would put the state's functioning at risk originating from Mariotto.

Juncker did, however, stress that if he had been asked to authorise the recording, he would have remembered.

The former prime minister explained that he had 'no specific' memory of authorising such a recording, and told the court that it is not the Minister of State's place to suggest wiretapping individuals. Instead, if the intelligence service asks, the Minister of State can authorise wiretapping, but it must also be approved by three judges in an emergency procedure.

Juncker, who concluded his mandate as European Commission president late last year, also told the court he could not remember a conversation about the wiretapping with then-SREL director Marco Mille, one of the defendants. The witness said that it could be possible that Mille had phoned him twice, as he was told, but he could not recall these events.

He added that he had wanted the alleged CD with a recording of a discussion between him and the Grand Duke decrypted.

On the first day of the trial, lawyers had motioned that Juncker should not be permitted to testify as they argued he had ordered the wiretapping of Mariotto and there was clear conflict of interest.

The details of the ominous conversation between Mille and Juncker, recorded by a modified watch (engineered a surveillance device) will be dissected in detail in Thursday's session.

For their part, the three defendants disputed being involved in the decision-making of the wiretapping incident, respectively explaining events from their perspective.

Fränk Schneider and André Kemmer both believed the wiretapping had been authorised. Mille described the case as unique and, following his interpretation, it had not been appropriate to seek approval from three judges.

The trial continues on Thursday.