that France could never enjoy the peace necessary to consolidate its control over Europe, and it could threaten neither the home islands nor the main British colonies. The Spanish uprising in 1808 at last permitted Britain to gain a foothold on the Continent. The Duke of Wellington and his army of British and Portuguese gradually pushed the French out of Spain and in early 1814, as Napoleon was being driven back in the east by the Prussians, Austrians, and Russians, Wellington invaded southern France. After Napoleon's surrender and exile to the island of Elba, peace appeared to have returned, but when he escaped back into France in 1815, the British and their allies had to fight him again. The armies of Wellington and von Blücher defeated Napoleon once and for all at Waterloo. Financing the war A key element in British success was its ability to mobilize the nation's industrial and financial resources and apply them to defeating France. With a population of 16 million Britain was barely half the size of France with 30 million. In terms of soldiers the French numerical advantage was offset by British subsidies that paid for a large proportion of the Austrian and Russian soldiers, peaking at about 450,000 in 1813. Most important, the British national output remained strong and the well-organized business sector channeled products into what the military needed. The system of smuggling finished products into the continent undermined French efforts to ruin the British economy by cutting off markets. The British budget in 1814 reached £66 million, including £10 million for the Navy, £40 million for the Army, £10 million for the Allies, and £38 million as interest on the national debt. The national debt soared to £679 million, more than double the GDP. It was willingly supported by hundreds of thousands of investors and tax payers, despite the higher taxes on land and a new income tax. The whole cost of the war came to £831 million. By contrast the French financial system was inadequate and Napoleon's forces had to rely in part on requisitions from conquered lands. Napoleon also attempted economic warfare against Britain, especially in the Berlin Decree of 1806. It forbade the import of British goods into European countries allied with or dependent upon France, and installed the Continental System in Europe. All connections were to be cut, even the mail. British merchants smuggled in many goods