What we do The absolute joy of a visit is you can see these guys operating Fourdrinier machines from the last century still making paper with the same process as the century before that. At Frogmore Paper Mill we celebrate the huge contribution that paper has played in shaping the world in which we live today. Frogmore Paper Mill is operated by the Apsley Paper Trail, a charitable trust founded to conserve the unique industrial heritage of this site in Hemel Hempstead. In 1803 Frogmore Paper Mill was the place selected by Henry and Sealy Fourdrinier for the trials of their newly patented paper machine. Thus began the paper's industrial revolution leading to the cheap, plentiful paper products that we all use every day of our lives. Frogmore is still a working paper mill but, as operated by the charity, it is also a visitor, education and community use centre as well. The trust is entirely self-financing and, of course, is not-for-profit with all proceeds from its activities being re-invested in the repair, maintenance and development of the mill and its historic equipment.