The 28km long waterway of Southampton Water is now one of Europe's busiest shipping routes - its best known feature is its double high tide which is caused by of the position of the Isle of Wight which gives the water two entrances.

In medieval times, the port prospered from the wool and wine trade. It was always of military importance - after the Norman Conquest in 1066, kings would use it as the main embarkation point for France.

The industrial revolution and the growth in world trade meant the waterway played a unique role, and was dredged and deepened to allow large cargo vessels - and great passenger liners - to ply up and down.

Japanese 'Sargassum muticum'