Tom Robertson, 68, was led to safety by mountain rescuers after a ten-hour ordeal on Ben MacDhui in theCairngorms. He and a pal had been hunting for the legendary Big Grey Man of BenMacDhui – Mountain of the Black Pig in Gaelic. But yesterday he insisted a 12ft high yeti-type creature attacked the tent he was sleeping in near the 4,296ft summit.He maintains he may have strong evidence of its existence – a series of pots showed 2ft long footprints in gravel at their camp site. Mr Robertson said; "At about 1am after we climbed in to our sleeping bags we heard the footsteps of something coming to the tent and heard mumbling noises outside.” Moments later the side of the two-man tent, perched 4,000ft up the peak, caved in. “I looked up through the air vent in the roof and saw a large arm crashing down. “The figure of what seemed like a yeti was standing over the tent, then all hell broke lose and it was trying to get on at us. “I remember something landed on my foot. My toes are black, kind of bruised. “I have never been so scared in all the 60 years I have been interested in such things. “I don’t know what it is but it wasn’t human. I reckon it could be the Grey Man or something from outer space.” The pair were soaking wet after heavy rain poured into the damaged tent overnight. At 4am they set off down the hill but almost two miles on Tom was too exhausted and fell ill half-way down. He was wrapped up in sleeping bags and left to rest. Pal Derek Blake, 32, battled on and raised the alarm three miles away at the Cairngorm Ski centre.