8 The reference to the video tape taken on 13 December 1993 is to a surveillance tape filmed between approximately 4.13pm and 5.52pm during which time the worker carried out work on a fibreglass boat which was sitting in its trailer at a service station run by the boat's owner. Earlier that day the worker had been seen by Mr McIntyre and had complained of symptoms and limitations upon his activities which Mr McIntyre, in the light of the tape, found inconsistent with the worker's apparent activities on and around the boat. There are breaks in the tape, there are obstructions in the form of fixed objects and passing traffic which restrict the camera's view of the worker from time to time and his activities while lying on his back under the boat and working on the hull are not fully observable due to constricted space and shadow. Nevertheless, it is clear that throughout a large part of the time the surveillance was carried out, he engaged in a considerable number of repetitious movements of wrists and forearms while cutting a hole in the hull to enable the fitting of a depth gauge without any sign of discomfort. He was also observed to lift his 3 - 4 year old son, holding him by the boy's hands, from a position on the ground up on to the boat, an activity which Mr McIntyre considered to be inconsistent with the grip strength demonstrated by the worker on clinical examination. The explanation offered by the worker for his activities was that Mr McIntyre had encouraged him that day to try to "work through the pain threshold" (a proposition Mr McIntyre did not deny), that although he had intended only to give advice to the boat owner, he had accordingly decided to tackle the job himself, that he did so at a considerably slower rate than it would otherwise have taken him, that he did in fact suffer discomfort while doing the work, "but not as much as the following day", and that when he was lifting the child the latter had himself been gripping the worker's hands.