Napoleon continued to be a great problem for Britain. He dominated continental Europe, meaning that people in Kent and across Britain found it very difficult to trade with Europe.
While Britain had a strong navy, France had a much bigger population and army. Eventually an uprising in Spain gave Britain a foothold in Europe, and the Duke of Wellington and his armies won victories across Portugal, Spain and Southern France. Meanwhile Napoleon had set off on his ill fated expedition to Russia in 1812-13. He then faced the armies of Russia, Austria and Prussia in1813-14. Napoleon eventually surrendered and was sent into exile on the island of Elba off the coast of Italy.
A year later he escaped, and Britain and its allies had to fight him all over again. The armies of Wellington and Blucher defeated Napoleon once and for all at the battle of Waterloo (in Belgium) in 1815. Napoleon was sent to a more remote exile on St Helena in the South Atlantic, where he died.