On returning from a navigation training exercise the Instructor asked the Student pilot to carry out a touch-and-go landing on Runway (RWY) 03. The approach with full flaps and landing was normal. On the ground roll prior to lift off the Student inadvertently raised the undercarriage. The aircraft settled fully on the ground and slid along for some distance before stopping. The crew shut down the aircraft and exited safely. There was no fire and no injuries.