The pilot had recently purchased the glider, and had previously made two short flights in it, for endorsement and familiarisation purposes. On the day of the accident he had trailered the glider to the launching strip, and had then assembled and rigged it for flight. A normal winch launch was carried out, with the glider releasing from the winch at about 1000 feet above the ground. It was then observed to be circling in a thermal, while gaining a further 500 feet of altitude. The angle of bank at this time appeared to be moderately steep. A witness then observed that the nose of the glider dropped and the aircraft commenced to spin to the left. It spun rapidly in a steep nosedown attitude, with occasional pitch oscillations, and recovery was not effected prior to impact with the ground. The subsequent investigation did not reveal any apparent faults or defects with the aircraft which might have led to the development of the accident. In addition, there was no medical evidence to indicate that the pilot was incapacitated or unfit to perform his duties as pilot in command. Although the pilot had received training in spin recognition and recovery techniques, he was possibly unaware that a spin could occur during an apparently normal thermalling turn. It could not be established when he had last performed spinning manoeuvres.