Economically and Militarily.
He attempted to Boycott UK goods from the Continent.
Geography helped Britain by providing a natural barrier against invasion due to being an island nation, making it difficult for Napoleon to launch a successful invasion. However, it also made it challenging for Britain to launch land offensives into Europe. Napoleon's military tactics and strategies posed a threat to Britain, leading to various conflicts and military engagements that impacted the country's resources and manpower.
One of the first actions for the participants during a war is to embargo all trade to your opponent. Trade from America to Europe had to go by sea and Britain, (the main enemy of Napoleon), had the largest navy, by a long way. Napoleon was using other European countries to place a trade embargo on Britain, so it was only right for Britain to do the same, which hurt trade to and from America. This was especially so between 1812 and 1815 when America declared war on Britain and her dependencies.
The first "fight against Britain" of Napoleon took place in the year 1793 at the siege of Toulon.
Britain?
Britain blockade Europe and costed Napoleon strength and money.
Britain
The country Napoleon was never able to conquer was Great Britain.
Great Britain was in constant opposition to Napoleon's Grand Plan.
Great Britain was able to fend off Napoleon's invasion thanks to the superior quality and skill in naval warfare of its fleet.
Great Britain
Britain's war with France meant Napoleon needed money.