Of Castlereagh's suicide, Bew gives us all the facts about the complete mental collapse that led to it, allowing us to make up our minds about the surrounding controversy. After ten years in two of the most stressful jobs in government, Castlereagh had a breakdown and cut the carotid artery in his throat with a penknife. It seems to have been a complete fantasy of his that he was being blackmailed over homosexuality, as he confided to George III the day before, not least because he wasn't homosexual. He was, however, paranoid, exhausted and depressed. Radicals like William Cobbett and Byron were jubilant at his death, but the truest epitaph was that of Field Marshal Sir Henry Hardinge, who pointed out that Castlereagh had died a martyr to his country, just as much as if he had been killed on the field of Waterloo.

Castlereagh was "surprisingly adept at making enemies", and these included Charles James Fox and William Wilberforce. Yet the greatest Britons of the day — giants such as Pitt, Nelson and Wellington — as well as foreigners such as Metternich, Talleyrand-Périgord and Tsar Alexander I all admired him, as have modern authorities such as Henry Kissinger. Shelley's accursed doggerel about murder will always dog him, of course, but Bew's book will save him in the eyes of anyone tempted to inquire into the subject of the slur. "I think those people who are acquainted with me," Castlereagh told the Commons in 1817, "will do me justice to believe that I never had a cruel or unkind heart." John Bew has done a fine job in acquainting us with him two centuries later, and we can wholeheartedly concur.