Former members of the Luxembourg secret service, the Service de renseignement de l'Etat (Srel), Marco Mille, André Kemmer and Frank Schneider will face trial from 3 to 13 March next year.

The trial has twice been postponed because of the unavailability of former prime minister and outgoing president of the European commission Jean-Claude Juncker, who is a key witness. Juncker said he could not make the original date in November 2017 citing EC commitments, and then he had to cancel his appearance at the rescheduled trial when he underwent surgery in early November, which led to the second postponement.

All three of the accused are charged with breaking data protection and privacy protection laws. Mille and Kemmer are also accused of illegally sharing a CD. The CD, which was codenamed “frisbee”, was encrypted but its content has so far not been accessed. It allegedly contains a recording of a conversation between Juncker and Grand Duke Henri. They also face charges of illicitly spying on Srel IT technician Loris Mariotto. The case could rest on whether Juncker, as prime minister and de facto head of the secret service, gave his authorisation for the agents to conduct surveillance on Mariotto.

Juncker told a parliamentary enquiry into the mismanagement of the secret service in July 2013 that he had not given his authorisation. But the accused have claimed they have evidence to the contrary, gathered from an illicit recording made by Mille using a microphone hidden in a now infamous wristwatch of a conversation with Juncker.

That enquiry led to Juncker asking the grand duke to dissolve parliament and call for the snap election that resulted in the CSV being ousted from government by the DP-LSAP-Déi Gréng coalition in December 2013.