Presumably if MB can show they used their best endeavours consistent with then current engineering practices they will have a good defence. The accident was very sad, especially for DC's family and friends, but it does seem HSE pursue a witch hunt at every opportunity. Anyone else seen the cartoon in the current Private Eye - bunch of guy storming a castle wall under a torrent of rock, boiling oil, etc. H&S guy at the bottom yelling - "Hey you, put your helmet on!" at a guy half way up the wall.