Touring in the peak district over the weekend we drove past a water reservoir on a hilltop - you know the sort - rectangular grassed over mound in a small compund - various hatches etc. on the roof. Didn't look quite right somehow. Nearby was another one with a sign saying Severn Trent Water, looked different to the first one. A couple of miles away was one like the first one, telephone connection, a small aerial like a TV aerial attached to an electrical cabinet in the corner of the compound and no Severn Trent Water signs again. This symbol was on a small sign by the gate: Any ideas? I thought that all the ROC bunkers were disused now. Perhaps they're just water tanks after all!