The pilot had completed an endorsement on the aircraft type two days previously, and intended to carry out a series of circuits with touch and go landings to consolidate his training. During the landing roll following the first touchdown, the pilot inadvertently retracted the landing gear when he attempted to raise the flaps. The aircraft slid to a halt on the runway. The instructor who had carried out the endorsement training was not aware that it was company policy to prohibit the conduct of touch and go landings for solo operations in retractable gear aircraft. He had therefore not briefed the pilot on this matter. The pilot stated that during his circuit training in the aircraft, which consisted of a series of touch and go landings, the instructor had raised the flaps after each touchdown. The pilot had only limited exposure to retractable landing gear aircraft types with the gear and flap controls laid out in a similar fashion to this particular aircraft.