The two are of totally different designs. Seymour, although the island's only square coastal tower, was otherwise typical of the round Conway Towers built in the 1870s and '80s. Icho is a squat, round tower, much more akin to the Martello towers built along the east coast of England at the same time.
Unlike many of Jersey's towers, the construction of Icho Tower can be accurately dated because General Don wrote on 4 January 1811 that "a tower was commenced by the Ordnance on l'Icho Rock last Summer, and it is now in sufficient forwardness to admit of a guard being mounted at it".
Along with all Jersey's other coastal towers and historic fortifications it is a listed building, described as follows in the Jersey Heritage Historic Environment Record website:
- "The tower and battery are significant as an integral part of a group of surviving military defences in Jersey that illustrates the changing political and strategic military history of the Island, and global trends in the history of war, in the late 18th and early 19th century through to the Second World War.
- "It is the largest of the series of towers of the English Martello pattern built in Jersey between 1831 and 1837.  The tower was built to a design approved by the Board of Ordnance and is a good example of the power of the ‘engineering architecture’ characteristic of work by the Royal Engineers in the 19th century.
- "The highest standards of construction were achieved by the supervising RE Officers and Jersey contractor Jean Gruchy and his stonemasons. The tower substantially retains its completeness and architectural integrity as an early nineteenth century tower with the structure close to its original form and physical context.
- "It is strategically sited and can still be read in terms of its strategic defence value as originally conceived. The stone battery similarly retains its integrity. The adaptation and re-use of the tower by the German occupying forces in the 1940s provides a direct and tangible association with events that are of outstanding universal significance. 
The tower is circular, 28 feet high, of dressed granite with a raised entrance and gun embrasures, and a traversing gun platform on top.
The tower's story
From the historyalive.je website
- "If you go to Icho Tower now, you will appreciate the difficulties that must have been encountered in building it. You can still see the remains of crude stone huts in which the quarrymen and masons building the tower in 1811 lived. They certainly didn’t get back to the 'mainland' every day and were dependent on not only the weather but tides for supplies and to get on and off. You can see parts of the islet reduced by quarrying to produce the stone as well as masons’ initials carved into the rocks (they probably had plenty of time on their hands at the end of their shifts).
- "You also see that there are only three windows and the door (accessed by a long ladder as all these towers were). But why three windows? They were to enable the garrison to see and receive signals from the adjacent towers. Two on the north side appear to face Platte Rocque and Seymour Tower respectively, and the one on the west seems to point towards Noirmont Tower and Fort Regent and Elizabeth Castle. It must be remembered that without telephone or radio at the time, line of sight signalling was imperative, and General Don, Lieut-Governor of Jersey, as part of the massive military building programme at the time, included a network of signalling stations around the Island so that any invasion risk was quickly communicated.
The Tower has had a private tenant for many years, who no doubt enjoys the solitude as well as a distinctly smelly seabird colony during their breeding season each year. The views are magnificent for those who have managed to get there.
From jerseywalkadventures.co.uk website
- "It is only possible to visit this area on very low tides.
- "As a result, very few people ever discover the marine life in this amazing place. It is rare to encounter more than a dozen people out low water fishing, catching lobster, prawns or shellfish.
- "Walk through sea gullies catching glimpses of the wider panoramas that suddenly open up to reveal a mass of reefs and sand bars.
- "Join local guides who have fished and foraged in this area for many years.
- ""Having been brought up with Icho Tower on my doorstep this is the area that most low water foragers consider to be Jersey's best", Derek Hairon."
Notes and references
- ↑ Archaeologists have found flints, pottery and human bones on the islet, suggesting that it was inhabited in Neolithic times, although it may not then have been an island, depending on where the sea level was. Icho has variously been known as Le Hyge Hoge (1563 map), Ickhoe (1685) and Croix de Fer (1645, 1737 and 1825). This is a reference to an iron cross which once stood there, but had long disappeared.
- ↑ This statement is incorrect. Icho may be larger than the other Martello type towers, but they were built much later. As indicated above, Icho was built in 1810-11
- ↑ The Germans made use of Icho but are believed to have left Seymour Tower alone