THE deadly cloud drifted in from the north east on a light wind, moving slowly the lethal fog seeped insidiously into the trenches manned by the Hampshire soldiers and the shout went up: “Gas, boys, gas!’’ Yellow-grey smoke, with its pungent, nauseating smell, engulfed the troops and just minutes later more than 240 men, who knew the country lanes, farms, and villages of Hampshire far better than the open downland of the Somme, were either dead or dying a terrible death.

See the list of names on Southampton Cenotaph

This was the effect of just one gas attack, on one summer’s day, during one battle of the First World War, with the whole, terrible incident, a microcosm of the slaughter, which took place in the trenches, bomb craters, and no-man’s-land of the “war to end all wars’’.

Today the nation will remember the dead of not only the First World War but of all the other conflicts across the decades in which British and Commonwealth servicemen have lost their lives in the fight against tyranny.

Almost a century separates the trenches of the Somme and today’s dangers in Afghanistan, but Hampshire soldiers are still answering the same call of duty and, in many cases, continue to pay the ultimate sacrifice.

The official account of the gas attack on the Hampshire soldiers is chilling in its use of words lacking emotion: “No attempt was made by the Germans to exploit what seemed to offer them a very favourable opportunity and attack: the gas, which was phosgene and particularly deadly, killing birds and rats for some distance in the rear and corroding metal, had been sufficiently effective.’’ After the first German gas attacks, British troops were supplied with masks of cotton pads that had been soaked in urine. It was found that the ammonia in the pad neutralised the poison.

Other soldiers preferred to use handkerchiefs, a sock, a flannel body-belt, dampened with a solution of bicarbonate of soda, and tied across the mouth and nose until the gas passed over. It was not until July 1915 that soldiers were given efficient gas masks and anti-asphyxiation respirators.

One disadvantage for the side that launched chlorine gas attacks was that it made the victim cough and therefore limited his intake of the poison.

Phosgene was more effective poison to use as only a small amount was needed to make it impossible for the soldier to keep fighting. It also killed its victim within 48 hours of the attack.

An estimated 91,198 soldiers died as a result of poison gas attacks and another 1.2 million were hospitalised.

The Russian Army, with 56,000 deaths, suffered more than any other armed force.

To coincide with the nation’s annual period of Remembrance, a new book has been published giving a gripping account of the actions that gave the former, Royal Hampshire Regiment, its proud battle honours.

The Battle Honours of the Royal Hampshire Regiment by Rupert Matthews highlights the fact that men from across the county have for generations fought in the ranks of the “Tigers’’, or its predecessors the North Hampshire Regiment and South Hampshire Regiment.

Among the brave actions featured among the Battle Honours are, Blenheim, Minden, Barossa, Kabul, Paardeburg, The Somme, Passchendaele, Dunkirk, D-Day and the Rhine Crossing.

An account of another engagement by the Hampshire soldiers at the Somme, again using typical British understatement says: “Our bombardment, despite its volume, had not fulfilled expectations. It had neither silenced the enemy’s batteries, subdued his machineguns, not shattered his defences.

“If hopes were high, those who had a close view could not avoid some misgivings after the volume of machine-gun fire provoked by a discharge of smoke.’’ It had unfortunately also been decided to fire a huge mine under the German lines, just ten minutes before “Zero Hour’’ and the Hampshire men went over the top and attack.

Up to then the German did not know when the attack would come but the large explosion gave away the element of surprise giving the defenders ample time to emerge from deep dug-outs, position machine-guns and, man parapets just us the British infantrymen, struggling with heavy equipment, began advancing across no-man’s-land.

The British first wave was almost immediately wiped-out by withering machine-gun fire, which according to the regimental history “mowed the soldiers down wholesale’’.

Then it was the turn of the men of the Hampshire Regiment who plunged forward into the deadly hail of fire, faring no better that their predecessors.

The majority of the Hampshires were brought down at, or short of, the coils of barbed wire, only a few reaching it, and the survivors could only seek the poor shelter of shell-holes, which pitted the battlefield, where the wounded laid for hours until darkness when they scrambled back to the trenches.

These events took place in the early part of the action at the Somme, which was one of the largest battles of the First World War. By the time fighting had petered out in late autumn 1916 more than 1.5 million casualties had been suffered by the forces involved, making it one of the bloodiest military operations ever recorded.

■ Battle Honours of the Royal Hampshire Regiment by Rupert Matthews is published by Bretwalda Books and costs, £7.99.