When did England and France set up blockades of the European coast and British isles

1807-11

Explanation : Napoleon’s Berlin decree of November 21, 1806, had already declared that the British Isles were under blockade and that “no ship which comes directly from England or the English colonies…shall…enter any of our harbours.” The secret Franco-Russian alliance of Tilsit furthered his scheme for economic warfare against Great Britain , since the cooperation of Russia should permit the complete closure of the Baltic to British shipping and hasten Austrian participation in the Continental System. Alexander undertook to support France against the British if they did not consent by November 1, 1807, to acknowledge the complete freedom of the seas and to return the conquests made since 1805. If Britain refused, France and Russia would “summon the three courts of Copenhagen, Stockholm, and Lisbon to close their ports to the British and declare war.”