ROC posts were used by the Royal Observer Corp during the cold war to amongst other things spot enemy aircraft and measure nuclear fallout in the event of attack. This one outside the village of Herstmonceux is one room and a toilet. It is in good condition and still contains 3 beds, cupboard, table and a chemical toilet as well as a tub of grease and several dead hares whether these managed to get in via an air vent and not escape or were put there to deter visitors with the stench i am not sure.