AT the Battle of Trafalgar in 1805, Horatio Nelson defeated a French fleet commanded by Napoleon Bonaparte’s brother Joseph.* The forty-one enemy ships he faced included many provided by the King of Spain, France’s ally; but on May 2nd, 1808, all Spain rose in anger after Napoleon’s troops occupied Madrid, and put Joseph on the Spanish throne.

Britain’s relations with Portugal were cordial, and with Lisbon’s help both army and navy were despatched to the Iberian Peninsula to bolster Spain’s fight for independence. At first things went badly: momentum gained by Sir Arthur Wellesley’s victory at Vimeiro in Portugal on August 21st, 1808, was squandered by the politicians. The defeated commander, Jean-Andoche Junot, Duke of Abrantès, offered complete surrender but under the terms of the Convention of Sintra the Royal Navy obligingly transported the French — their troops and guns and even the loot they had taken from the Portuguese — safely back to France. Wellesley protested, as did the British public, but to no avail.