The defences you can visit on the west coast of Jersey cover more than two hundred years of history and include well restored WW2 and Napoleonic towers. The map shows how open and inviting the terrain is for invasion, hence the need for defences!

Visiting Jersey west coast defences
As you can see from the map, a single road runs the length of the coast. All the sites were well signposted and had parking areas although I don’t remember there being any facilities available at all. Saying that, there is not exactly a shortage of cafes along this stretch of road!
My Experience
These defences are well restored and maintained and it is lovely to be able to walk around things that aren’t just crumbling ruins! It was also nice to see military recycling as each set of defences was upgraded or modified to suit the current technology.
Jersey west coast defences Photo Gallery














History
Coastal towers stand all along the coast of the island. The British built 22 round towers, one similar square tower, and eight Martello towers towards the end of the 18th Century and in the early to mid-19th Century, but now only 24 remain, including seven of the Martellos.[5]
Conway’s towers
Archirondel tower, Jersey
Model of the tower
On 28 May 1778 the Governor of Jersey, Field Marshal Henry Seymour Conway, submitted plans to Lord Weymouth for the construction of 30 coastal towers to forestall, or at least impede French incursions on the island. King George III granted approval and funding on 5 July 1778.
Work began in 1779, after a failed French landing at St Ouen’s Bay on 1 May 1779. Perhaps four had been completed by the time of the Battle of Jersey in 1781, in which however they played no part. Guernsey, which the French did not attack, had built 15 loophole towers between 1778 and 1779.
Seymour Tower, which replaced an earlier tower on the same spot at La Rocque, was built of granite and was the only square tower. The other 22 towers that Conway had constructed were round.
Although frequently called Martello towers, the round towers are taller, and they predate the development of true Martello towers. The round towers differ from Martello towers in several ways. The Jersey towers are mostly built with local granite rather than brick, have a slighter batter (taper), and most importantly, originally did not have a cannon on the top platform. (The Guernsey round towers have a strong batter on the ground floor and no machicolations; they too initially did not carry a gun on the top platform.) Later, at the onset of the Napoleonic Wars, both the Jersey and Guernsey towers each received a 12-pounder carronade on a pivot mount for the top platform.
The British built eight true Martello towers in Jersey, three between 1808 and 1814, and five between 1834 and 1837. The German occupation forces destroyed one of the second group, L’Etacq, during World War II.
During World War II Nazi Germany constructed a considerable number of fortifications in the Channel Islands which form part of the Atlantic Wall. The Channel Islands were amongst the most heavily fortified parts of the Atlantic Wall, particularly Alderney which is the closest to France. In Jersey, the fortifications include Hohlgangsanlage tunnels and artillery batteries such as Battery Moltke and Battery Lothringen.
The most distinctive new structures the Germans built were the Marine Peilstand (MP) towers that they used to search for targets at sea. The Germans had intended to build nine towers, but only completed three. These towers are round and have five or more floors with observation embrasures, as well as defensive embrasures. MP1 is part of Battery Lothringen, MP2 overlooks Corbière lighthouse and is now known as the Radio Tower, and MP3 is part of Battery Moltke. The design of the towers inadvertently and somewhat ironically reflect the Bauhaus movement of Modernist architecture (1919-1933), a movement that the Nazis had tried to suppress.
As well as building many new fortifications, the German forces made their own additions to some of the existing fortifications. These additions include gun emplacements and various types of bunkers.
Organisation Todt built the fortifications using imported labour, primarily prisoners of war and workers deported from occupied countries. The Germans transported over 16,000 slave workers to the Channel Islands to build the fortifications.
References
Wiki has a superb page covering all this information here. The history above is an abridged version of that page.

