'Me, my dad and the unanswered questions of Piper Alpha'

Iona Ballantyne's late father Bob was one of 61 survivors of the Piper Alpha disaster in 1988.

The deaths of 167 of his colleagues when the platform exploded had a profound impact on him, and he became a vocal campaigner for offshore safety.

His daughter met Lord Cullen - the judge who headed the public inquiry into what went wrong - and he told her he still worries that offshore workers may not feel able to speak out about safety fears.