By Hamish MacPherson Glen Fruin, between Gare Loch and Loch Lomond, saw one of the bloodiest clan battles ever fought IT was on this date in 1603 that one of the bloodiest and certainly one of the most one-sided of all clan battles was fought between Clan MacGregor and Clan Colquhoun in Glen Fruin, which lies between Loch Lomond and the Gare Loch. Nowadays the Glen contains the A817 which is the upper route to the nuclear submarine base at Faslane. And for convenience sake I will refer to the clan as MacGregor, though I know there were and are different spellings.