The pilot was conducting a night cross-country exercise to maintain his recent experience requirements. On final approach he realised that the aircraft was undershooting. Some engine power was applied and the approach was continued but the pilot then saw power lines ahead, too late to take any avoiding action. The aircraft struck the wires and subsequently impacted the ground 211 metres short of the threshold. It came to rest 91 metres further on after colliding with a fence. The wires struck provided power for the airfield lighting, which was extinguished at the time of collision. The power lines struck were 28 feet agl and were 600 metres from the threshold. The pilot had been slow to realise that the undershoot situation was developing and had not taken appropriate action to either regain the normal approach path or to go-around.