Don't know about security guards Keith but at Netherton we had a 'colliery polis', nothing to do with the men in blue brigade but on the payroll at the colliery. I'm not sure if it was a full time job or if he worked as a miner as well. The one I remember from the 50's was called Geordie Collis. He was a giant of a man and we kids were terrified of him. He was everywhere in the colliery, not just around the pit itself but around the houses and school as well, seeing that we kids didn't get up to mischief on colliery property. It wasn't hard for him to find offenders. We lived in a colliery and everything around us was owned by the colliery! I can distinctly remember him coming to the school one day and giving all the assembled children ( 2 classes of 5-8 year olds) a stern warning about destroying lupins in the school garden.