Facility 1391 has been airbrushed from Israeli aerial photographs and purged from modern maps. Where once a police station was marked there is now a blank space. Sometimes even the road leading to it has been erased. But Israel's secret prison, inside an army intelligence base close to the main road between Hadera and Afula in northern Israel, is real enough. For 20 years or more it has been housed in a large, imposing, single-storey building designed by a British engineer, Sir Charles Taggart, during the 1930s as one of a series of garrison forts designed to contain growing unrest in Palestine. Today, the thick concrete walls and iron gates are themselves protected by a double fence overseen by watchtowers and patrolled by attack dogs.
"Our main conclusion is that it exists to make torture possible - a particular kind of torture that creates progressive states of dread, dependency, debility," says Manal Hazzan, a human rights lawyer who helped expose the prison's existence. "The law gives the army enough authority already to hide prisoners, so why do they need a secret facility?"
Unlike any other Israeli prison, the International Red Cross, lawyers and members of the Israeli parliament have been refused access.
It is not just human rights lawyers and leftwing MPs who have a problem. Ami Ayalon is a former head of Israel's intelligence service, the Shin Bet. He was told about 1391 but says he refused to have anything to do with it.
"I knew there was a facility not under the responsibility of the Shin Bet, but under the responsibility of the military. I didn't think then, and I don't think today, that such an institution should exist in a democracy," he says.