Given the proximity to occupied France, Sussex was vital in the build up to D-Day. Americans and Canadians were camped here in their hundreds of thousands and towns and usually serene villages were swamped with tanks and heavy artillery.

BY THE spring of 1944 whispers were spreading. The South Downs resembled a mass army base, as half the Allied forces had set up camp.

Cricket grounds had been taken over by Americans playing baseball, tanks rumbled through picture postcard villages and the top brass from both sides of the Atlantic had been spotted.

Everyone knew something was about to happen but nobody knew where or when.

From the start of the year, troops began to arrive in Sussex.

There were camps far and wide and headquarters set up at many of the country houses.

The US Army 188th Field Artillery Group, 951st Battalion Field Artillery and 105th Medical Battalion were at Arundel, 15th Scottish Infantry at Cowfold, 3rd Battalion and 120th Light Infantry at Felpham and 51st Heavy Regiment at Rudgwick, to name a few.

Stanmer Park, Brighton, was one of the main camps with 2,800 men from the British 3rd Infantry Division. They left from Shoreham and Newhaven for Sword Beach.

The Americans in particular caused quite a stir on their arrival. While some found them brash, loud and obnoxious, most Sussex residents welcomed them.

Residents were known to invite groups of soldiers in for cups of tea and cake (despite the stringent rationing) and elsewhere canteens were opened.

Some even went out of their way to make the Americans feel at home. In Middleton a Mr and Mr Vigur set up a cafe known as Mom and Pop’s Canteen.

Entrepreneurial youngsters also befriended the troops. Don Broughton, a teenager who was living in Westbourne at the time, recounted how he set up a courier service ferrying fish and chips to the GIs. In return he was given candy and chewing gum.

However, not everyone was overjoyed by their arrival.

A considerable amount of the Duke of Norfolk’s land, covering Angmering, Burpham, Clapham and Patching, was taken by the War Office for training. The Americans ran their tanks and heavy artillery all over it leaving the landowner unable to farm for two years.

Compensation was paid, but good will was relied on – as it had been throughout the war.

By the spring of 1944, the Americans were arriving at a rate of 150,000 a month and brought with them 750,000 tons of supplies.

In Littlehampton there was one of the more important bases in Sussex – yet little was or still is known about it.

Ten Commando or X Troop, as they are otherwise known, was made up of volunteers from various regiments of the Allied forces. They included many Germans, with extreme anti Nazi views, Eastern Europeans and Jews. One thing they all had in common was that they were vicious, trained killers.

Led by multi-linguist maverick Captain Bryan Hilton-Jones, each of the members of the unit of 72 had their own cover story, linking them to regular regiments of the army.

They had raided various defences along the French coast in the winter of 1943/44 in a bid to confuse the enemy of where the invasion would take place.

But in the build up to D-Day they were stationed in Littlehampton and used the surrounding countryside for training.

Their programme included bivouacking, abseiling, use of dinghies, silenced weapons, night firing, use of homing pigeons and brutal hand-to-hand combat.

They were also known to march from the Black Rabbit pub near Arundel to Littlehampton in 39 minutes for endurance.

Residents in Arundel spoke of how one night they carried out a practice assault on the castle.

By June 6 they had all gone to France, with half killed or wounded. It was not until 1946 their existence was acknowledged by authorities.

With the day moving ever closer, key commanders and even the King were spotted in Sussex, further hinting invasion was imminent.

On April 19, General Eisenhower, the supreme commander of the operation and later to become US President, travelled to Chichester and stayed at the Ship Hotel in North Street. From here he inspected nearby airbases to ensure all was ready.

On April 21 he was guest of honour at a special dinner in the officers’ mess at RAF Tangmere.

The following month the King, George VI, journeyed to Petworth Park to inspect the 27th Armoured Brigade. With the Hussards band playing he travelled along the line in an armoured half-track before getting out and speaking to a few of the men.

However, with German spies throughout the south of England, the authorities knew they had to be careful not to give away their plans.

As well as banning troops from talking to members of the public about operations they devised a cunning plan in Worthing.

The British commander-in-chief General Montgomery, was sent to rally the troops at Broadwater Green ahead of invasion. However it was not Monty – as he was known among the ranks – but his double Clifton James dishing out false information. That information was relayed back across the Channel. The plan had worked.

Not only was the county used as a launch pad for invasion but also as a practice ground.

While details were kept from the troops, they were aware the operation would likely be seaborne.

This was confirmed in early 1944 when a number of practice runs were held at Bracklesham Bay.

Landing crafts, tanks, aircraft and thousands of troops all took part in the highly secretive drills.

Roads surrounding the bay were closed off with armed guards while the Dad’s Army ordered people to stay in their homes.

However, even during the practice runs not everything went to plan. Vehicles got caught on defences, troops were injured and bungalows demolished by out of control tanks.

A mass final rehearsal was held in mid-May with thousands landing between Littlehampton and Bognor and at Bracklesham and Hayling Island in Hampshire.

Meanwhile, infantry units and commandos rampaged through towns and villages further north including Middleton and Arundel in an attempt to replicate the fierce house to house fighting they would face in French villages.

It is said Eisenhower, Montgomery and Prime Minister Winston Churchill watched the practice run from the Bracklesham Bay Hotel near Selsey.

When the signal was finally given, troops made their way to Shoreham and Newhaven in their tens of thousands.

While the main invasion force disembarked from Portsmouth, many of those destined for Gold and Sword beaches left the country through Sussex.

Within hours the county had emptied. Villages and towns fell silent, roads deserted and camps left with nothing more than a few muddy tracks.

Those who had been staying in Sussex for weeks and in some cases months had embarked on the greatest seaborne invasion of all time.

Many would not return.