Plays and novels have been written and documentaries made about the mysterious disappearance of Donald Crowhurst at sea in the late 60s - it's easy to see why. His is a fascinating story.
Donald Crowhurst (Firth) was an inventor, father of three, and amateur sailor from Bridgwater, England, who surprised everyone by announcing he would enter the Sunday Times Golden Globe single-handed round the world yacht race in 1968. An engineer by trade, Crowhurst designed and built a catamaran for the journey, but was forced to begin the race in a boat ill-equipped for the journey ahead.
It didn't take him long to realise he wouldn't survive the Southern Ocean and he was faced with the decision to carry on regardless, or head for home, humiliated and bankrupt.
He decided on a third option. Instead of following the race route he pottered around the Atlantic with the intention of re-joining the race as it neared the final destination of England; in the meantime, entering false race reports to organisers, family and his public relations crew.
It's an intriguing story and James Marsh (The Theory of Everything) directs a talented and committed cast, but it proves tricky to bring to life on the big screen.