The dispute had its origins in the Walcheren Expedition – a disastrous military campaign in the Netherlands, which took place in the latter half of 1809. The expedition was intended to open another front in the Austrian Empire's struggle with France during the War of the Fifth Coalition.
Castlereagh, as Secretary of State for War, was widely blamed for the failure of the landing on the Dutch coast, which Canning (as Foreign Secretary) claimed to have dismissed as an ill–advised, ill–prepared diversion of troops from the Peninsular War. Castlereagh had the support of General Wellesley (the future Duke of Wellington), and evidence later surfaced that Canning himself had interfered with the plan. The government of the time, led by the Duke of Portland, became increasingly paralysed by disputes between the two men. Portland was in deteriorating health and gave no lead, until Canning threatened to resign unless Castlereagh was removed. Portland secretly agreed to make this change when it would be possible.
Castlereagh discovered the deal in September 1809, and challenged Canning to a duel. Canning accepted the challenge and it was fought on 21 September 1809 on Putney Heath. Canning, who had never before fired a pistol, widely missed his mark; but Castlereagh, who was regarded as one of the best shots of his day, wounded his opponent in the thigh. There was much outrage that two cabinet ministers had resorted to such a method. Shortly afterwards the ailing Portland resigned as Prime Minister, and Canning offered himself to George III as a potential successor. The King appointed Spencer Perceval instead, and Canning left office once more. He took consolation in the fact that Castlereagh also stood down.
Six months later, Canning published a full account of his actions in the affair, but many who had initially rallied to him became convinced that Castlereagh had been betrayed by his cabinet colleague.
Upon Perceval's assassination in 1812, Canning was offered the post of Foreign Secretary by the new Prime Minister, Lord Liverpool. Canning refused, as Castlereagh was also expected to be in Liverpool's Cabinet, and Castlereagh took the job. He co–ordinated European opposition to Napoleon, and represented Britain at the Congress of Vienna (1814–15).
Subsequently, at home, Castlereagh supported the repression of the Reform movement, and popular opinion held him responsible for the Peterloo Massacre of 1819. Widely reviled in both Ireland and Great Britain, overworked, and personally distressed, he committed suicide in 1822.
Lord Liverpool then offered the position of Foreign Secretary to Canning once more, and this time he accepted. In April 1827, when Lord Liverpool resigned, Canning was chosen to succeed him as Prime Minister, ahead of the Duke of Wellington and Sir Robert Peel. Both of them declined to serve under Canning, and the Tories split between the Ultra–Tories (led by Peel and Wellington) and the Canningites. Canning then invited several Whigs to join his cabinet. But his health soon collapsed, and he died in office in August 1827. His tenure of only 119 days in office made him the shortest–serving prime minister in history, a title he held for 195 years – until Liz Truss came along.
© Haydn Thompson 2023