He wanted to blockade all incoming trade from Britain.
The British navy had other ideas and trade got through.
It looks as if Boris Johnson, by sticking to the position that the EU needs to give Britain the same trade terms and conditions that she had as an EU member - an idiotic proposition on its face - and Covid 19 by mutating in London and south England are going to accomplish the blockade.
The UK is an island with a little chunk of territory on an adjacent, smaller, island.
For centuries that was an advantage.
If you were going to win wars by being the balancer of power, having had a little time, space and distance to study the options was always an advantage.
Recently, however, the insular mindset that that historic fact has carried into current times has proved to be increasingly damaging: 75 million people on a couple of islands are not going to compete very well with 1.2 billion people who have the world's second largest economy and currently own most of Africa, or with 450 million people just across the water from them who have in aggregate the world's second largest economy (China is counted differently; it uses the Big Mac Index) or even with the 320 million people who live in its former colony in North America.
As the boats, trains, planes and lorries stack up off island and quickly turn to other endeavors it is going to be interesting to see how far a stiff upper lip goes these days.