Can one day really change the course of history? Andrew Hitchon examines how June 6, 1944, helped to shape modern Europe.

IT WAS the mightiest invasion fleet ever assembled, and the course of history rested on its success or failure.

A great armada, protected by aircraft which swept the skies over the English Channel and the French coast, took more than 130,000 men to the Normandy beaches to begin the crucial last phase of the battle to free Europe from Hitler.

Allied forces were already fighting their way up the Italian mainland - they had taken Rome just two days before the D-Day landings.

And on the borders of Poland the Red Army was poised to launch another great offensive against the German invaders who had once reached the suburbs of Moscow.

The greatest battles of the Second World War, certainly in times of numbers and casualties, were fought on the Russian Front. But Hitler himself had no doubt about the importance of the long-awaited invasion of France. Early in 1944, he told his generals that while vast tracts of land could be lost in the east without posing a threat to the Reich, if the Allies established themselves in France, they could soon be at Germany's borders.

The same invasion was awaited with something approaching dread by Britain's leaders. Churchill and his chief military adviser, Alan Brooke, both feared a repeat of the carnage of the First World War - and that the invasion might fail.

The Americans had long championed the invasion, but the Allied supreme commander, Dwight Eisenhower, had prepared a statement explaining the mission's failure - and taking full responsibility for it.

Could the invasion have ended in disaster? It is sometimes forgotten just how uncertain a venture a cross-Channel invasion was. The weather caused Eisenhower to cancel the original invasion date, June 5, and posed him a big problem on D-Day itself. Luckily, "Ike" made the right decision and Operation Overlord went ahead. If he had waited, then the invasion might have been rescheduled for later in the month - possibly right in the middle of the "Great Storm", which smashed one of the Mulberry artificial harbours, and could have wrecked the crossing itself.

Any delay would have increased the risk of the Germans guessing the true destination of the invasion, and moving crack formations from the Calais area to Normandy.

If the invasion had failed, the consequences for Europe would have been grim indeed, including possibly a completely Soviet-dominated continent, or even an extension to the life of the Nazi regime. But, as the thousands of veterans returning to France this weekend will tell you, the invasion didn't fail. Despite stern opposition on some of the beachheads, by the end of June 6 the Allied servicemen had gained a vital foothold in France, and though a Panzer unit managed one attack before the end of the day, they were not to be shifted.

From then on Hitler's Reich was doomed, although there was bitter fighting ahead in the Norman countryside in the weeks before the Allied breakout.

As Rommel famously observed, June 6 was the "longest day", because it was the one day when the battle could go either way. The veterans celebrating this weekend, and their comrades, made sure it went the right way.

The might of the armada

THE D-Day invasion fleet comprised some 7,000 ships, while 11,000 aircraft flew overhead.

More than 130,000 men were landed in Normandy that day. Many of those came ashore on the five invasion beaches - Omaha and Utah (American), Gold and Sword (British), and Juno (Canadian).

In addition, British and American airborne troops were dropped inland from the beaches, with the tasks of disrupting German responses to the invasion, and seizing key objectives, such as the Merville Battery and the Pegasus Bridge, both of which were taken by the British 6th Airborne Division.

The highest losses of the day were on Omaha Beach, where American troops were pinned down by German fire. At one point US First Army commander Omar Bradley considered evacuating the beach and taking his men to one of the others, but eventually the troops rallied and fought their way inland. They suffered 2,400 casualties. Losses on Utah Beach were relatively light, while the British and Canadians suffered about 3,000 casualties across their three beaches.

Updated: 12:22 Saturday, June 05, 2004