Not even the battlefield tour guides have heard of Richebourg.

It is an insignificant speck on the map of France, to the north-east of a town called Bethune.

Most people from Sussex disembark from the ferry at Calais and drive straight past on the A26 motorway, heading for Paris or Provence.

But only a few kilometres from the motorway lie the remains of hundreds of soldiers from Brighton, Hove, Worthing, Battle, Haywards Heath, Hastings, Eastbourne, Hailsham, Chichester, Steyning, Poynings and Glynde.

Richebourg, a tiny village where farming is the mainstay of life, is surrounded by small, lonely cemeteries maintained by the Commonwealth War Graves Commission.

Each one contains row upon row of white gravestones bearing the crest of the Royal Sussex Regiment.

The same chilling date is inscribed on every one of them, signifying what became known after the Great War as "The Day Sussex Died".

At 3.05am on June 30, 1916, three battalions of the Royal Sussex, the 11th, 12th and 13th, went over the top following a 15-minute bombardment of German trenches.

For many of the young soldiers, it was their first and last time in action.

Within the space of several hours, 366 officers and men (including 12 sets of brothers) were dead and more than 750 wounded.

The Sussex lads bombed and bayoneted their way into the enemy lines and beat off repeated counter-attacks until they were forced to withdraw as casualties mounted and ammunition ran out.

Sergeant-Major Nelson Victor Carter, 29, a cinema door attendant from Hailsham, won a posthumous Victoria Cross for exceptional bravery under fire.

His citation read: "During an attack he was in command of the fourth wave of the assault. Under intense shell and machine gun fire he penetrated, with a few men, into the enemy's second line and inflicted heavy casualties with bombs.

"When forced to retire to the enemy's first line, he captured a machine gun and shot the gunner with his revolver.

"Finally, after carrying several wounded men to safety, he was himself mortally wounded and died in a few minutes.

"His conduct throughout the day was magnificent."

The Argus visited his final resting place, in a cemetery near Richebourg and laid a wreath of poppies at the grave, which bore a carving of the VC underscored by the words: "For Valour."

The visitors' book, protected from the elements in a small vault, revealed that several people from the Eastbourne area, including a relative of Carter, had visited in the past year.

It was comforting to know that at least Carter was remembered but the visitors' book at another cemetery dominated by Royal Sussex graves painted a much gloomier picture.

I was the first person from Sussex to visit St Vaast Post, Richebourg L'Avoue, for at least a year.

Among those buried here were Sgt J French, 24, from Storrington; L-Cpl E W Tester, 30, from Brickyard Cottage, Ardingly; W J Wickens, 19, of Gladstone Terrace, Hastings; Pte E G Collins, 20, of Simla, Park Road, Worthing; Pte H Mercer, 18, of Steer's Green, Battle; Pte C J Brown, 20, of 27 Norfolk Road, Littlehampton; Pte W N Pumphrey, of 3 Wakefield Road, Brighton, and Pte John Henry Bugden, 28, also of Brighton.

Walking among the graves, I wondered how they died, what their last thoughts were and how many children they left behind.

All around the land over which they advanced to their annihilation 84 years ago was flat and featureless.

The German machine gunners must have had a field day, cutting swathes through the advancing ranks of British Tommies.

The carnage was so horrifying that survivors later branded the battlefield "a butcher's shop".

I called on the Mayor of Richebourg, Ginette Delestrez, and presented her with a Royal Sussex Regimental plaque inscribed: "To the people of Richebourg, from the citizens of Sussex. October 2000."

We toasted each other with champagne but she was not aware of how many Sussex men were slaughtered in the fields around her home.

Richebourg was flattened by shellfire during the war, leaving the surviving population destitute.

After the Armistice, Worthing launched an appeal to help rebuild the shattered houses and feed the residents.

Dignitaries from Richebourg visited Worthing, and vice-versa, but the link forged all those years ago has long since been severed.

Madame Delestrez showed me an oil painting, desperately in need of a clean after decades of exposure to cigarette smoke, on the wall of the community centre.

It depicted the haunting scene of a British Army chaplain on horseback conducting a church service on the battlefield.

The village historian flicked through a book on Richebourg but there was no mention of the Royal Sussex.

But this was no surprise, as most books about the Great War are also devoid of information on the battle.

But why have the three battalions, nicknamed Lowther's Lambs after the Hertsmonceux MP Claude Lowther, who raised them, been forgotten?

The following day, the Battle of the Somme began and 20,000 British soldiers perished in a single day.

In the great scheme of things, Richebourg was simply a "minor" diversionary attack. The generals effectively sacrificed the Royal Sussex for no strategic gain.

Now, as the Great War fades from memory, surely as a county we should do more to remember the victims of Richebourg?

They may have died almost a century ago but they were still Sussex born and bred.

And they are resting a long, long way from home.

The Argus travelled from Dover to Calais courtesy of SeaFrance. From Calais, it it just a short journey down the A26 to the battlefields. To book a crossing, phone 08705 711711.