Picture the scene. It’s Monday, 5 June 1944. The moon is full; the tide is high. Thousands of ships lie at anchor in the Solent. Thousands more troops await their orders.  As midnight approaches, there’s a flurry of activity. Operation Neptune is underway.

Build-up berthing plan of Southampton and Portsmouth for D-Day

It’s an apt codename for the largest seaborne invasion in history. Made up of almost 7,000 craft, from battleships and landing craft to merchant ships and midget submarines, and transporting some 132,600 assault troops, Neptune was the maritime arm of Operation Overlord, the Allied invasion of German-occupied France that proved to be the turning point of World War II.

Ahead of the armada went almost 300 minesweepers, clearing a safe passage through ten individual channels to the beaches of the Normandy coast.

Years of intricate planning had focused on this moment, with a near-incessant build up of troops, ships, tanks, weapons, landing craft and supplies right across the south coast of England, from Cornwall to the Thames Estuary. In the Solent, the naval ports of Portsmouth and Southampton were key to the operation, but the web of preparation spread to numerous towns and rivers, from Lymington, Beaulieu and Calshot to Yarmouth and Cowes on the Isle of Wight.  The airfield at Lee-on-Solent played a hefty role, as did parts of the New Forest, which served as training and gathering grounds for troops.

As the clock ticked down, the Solent became choked with vessels; witnesses report that it would have been possible to walk from the Isle of Wight to the mainland without getting your feet wet.

Yet by the early hours of 6 June, the entire fleet had vanished. For the soldiers on watch at Hurst Castle that morning, the massive conglomeration of ships must have seemed like the stuff of dreams.

The vacuum was soon to be filled.  On-the-ground troops in Normandy needed a constant stream of reinforcements and supplies; passage back to England was required for wounded soldiers and prisoners.  Once again the Solent came into its own.  Between 7 June and the end of July,  well over half a million more men were ferried to France, along with a further 137,249 vehicles. In their place came some 53,000 wounded soldiers for treatment at hospitals along the coast, and nearly 35,000 prisoners.

For the Solent and the surrounding villages, towns and cities, the years of planning and execution of Operation Neptune represented the greatest historical role that the area has ever seen.