Police say youngsters who are playing around a disused factory in Glossop are risking their lives.
Officers say they have had "multiple" calls recently regarding young people being on and in the old Volcrepe site - the last remaining buildings and structures which were part of the Old Woods Mill site.
Volcrepe Ltd was a large former rubber producing factory in Glossop, formed in 1931 and based in the 200-years-old Woods Mill.
Glossop Police Safer Neighbourhood Team say the site is "exceptionally dangerous" and is asking parents to make sure that their children and young people stay away from the location at all times - particularly during the summer holidays and in nice weather when the temptations are greatest.
Among the dangers are loose or falling roof tiles, walls or fences that could collapse, hidden or unknown dangers, broken glass and other hazardous materials.
Officers say their message is simple - "Stay Safe - Keep Out".