Murder Island features eight real-life ‘ordinary people’ seeking to solve a fictional killing on a fictional Scottish island. What follows is so confused and confusing that you can only imagine it was pitched to Channel 4 as ‘Broadchurch meets The Apprentice’ and nodded through as a result, without anybody asking such pesky questions as ‘So how might that work, then?’ Or if they did, that they were silenced by the news that Ian Rankin was signed on as the writer — whatever that might mean, seeing as most of the programme is necessarily unscripted and the investigation itself impossible to...