An author publishes a novel featuring a character named Tom Riddle, a politician accused of corruption. The character is clearly based on Tim Raddle, a real local councilor, and the novel includes detailed allegations of bribery that mirror actual news reports. Raddle is fired and sues for libel. At trial, the author proves that the core allegations of bribery are true, though some minor details (such as the exact date of a meeting) are incorrect. Which defence is most likely to succeed?