he was then transferred to mainland france where he was imprisoned first at marseille, then at clermont-ferrand and thirdly at gannat (a small town in the hills between clermont-ferrand and vichy. after approximately nine months of pre-trial detention, it was at gannat that claude hettier de boislambert faced a court martial on 13 june 1941. the death sentence which the court conferred on him was immediately commuted to "forced labour in perpetuity". initially he was now taken to another prison, this time in saint-etienne, where conditions were particularly harsh. later he was taken back to the prison at gannat. at the end of 1942 he managed to escape, probably from a labour gang, which ended a period of detention that by now had extended to approximately 26 months. he spent a couple of months living "underground" (unregistered) in france and was then returned to the presence of the général in london. the return involved what one source describes as "an aerial operation in the region of clermont-ferrand", which was undertaken during the night of 14/15 january 1943.