Defying the Iranian regime from the inside

Mohsen Sazegara was at the heart of Ayatollah Khomeini's regime from the moment the spiritual leader returned to Iran from exile.

Throughout the 1970s Sazegara had been a student activist agitating for the overthrow of the Shah. In 1979 he became Khomeini's press attache. He also helped found the now feared Revolutionary Guard, originally established as a defence force against possible attack from Israel or the United States.

As the Islamic state was established, dissenters were executed in their hundreds. But then factions within the regime began to turn against Mohsen Sazegara who was pressing for greater co-operation with opposition groups.

It was a path that would lead to his imprisonment - and eventually to exile in the West. But not before he witnessed for himself what really happened inside Tehran's Evin prison, as he explains to Fergal Keane.

Taking a Stand is on BBC Radio 4 on Tuesday 14 December at 0900 GMT and repeated at 2130 GMT. Or listen via the BBC iPlayer.