Hats off to Rona Fairhead, the former Financial Times executive who will succeed Lord Patten as chairman of the BBC Trust. It requires a brave spirit to take on this poisonously politicised role — and Fairhead starts with the disadvantage that everyone thinks they know the roll call of candidates who might have been preferred but declined to apply, including her own former boss Dame Marjorie Scardino, for whose job as head of Pearson, the FT’s parent, Fairhead was passed over last year.