The Scottish soldiers whose heroism during the First World War earned them the Victoria Cross

German forces had been pursued by French and British forces as far as the north bank of the Aisne but had been able to establish a foothold on high ground above the river.

The 1st Cameron Highlanders suffered badly as they tried to advance on the Aisne on September 14. The company commander, Lieutenant James Matheson, scion of a wealthy landowning family in Sutherland, was severely wounded near the village of Troyon. Tollerton dashed to his side and lifted him on to his back with the help of a sergeant, who was promptly shot dead.

Tollerton carried Matheson to a quiet part of a nearby cornfield before returning to the battle, during which he sustained several wounds. Rather than obey an order to withdraw, however, he returned to Matheson's side, determined to take him to safety.

And for three days Tollerton and Matheson, both wounded, gave each other the strength to survive. Such was the German presence that escape was impossible. All that the two Scots had was a water bottle. It was a small mercy.

At length, Tollerton was so weakened by blood loss, exposure and hunger that it would have been a real effort to carry himself very far, let alone his comrade. But when the Germans abandoned the area by the third day he spotted his chance and was able to contact a friendly trench-digging party.

Matheson had suffered serious spinal injuries and both men were invalided back home. Tollerton received the VC from King George V in front of 50,000 spectators on Glasgow Green in May 1915. He ended the war as a sergeant, and afterwards he saw service with the territorials and worked as a school janitor. He died in 1931, one day after turning 41. His funeral in Irvine was exceptionally well-attended, and among the wreath-layers was James Matheson, the man whose life he had saved. Matheson himself lived only for another two years, never having fully recovered from his wounds

The poet Wilfred Owen, in Dulce et Decorum Est, caught, brilliantly, the consequences of a gas attack on the trenches: Owen writes of one soldier, unable to put his helmet on in time, "flound'ring like a man in fire or lime ... guttering, choking, drowning".

Such must have been the perils facing soldiers on both sides at Loos, on the Western Front in France, just over a century ago, on September 25, 1915. Five months previously, the Germans had used chlorine gas at Ypres, in Belgium, but now the British Expeditionary Force were able to call on gas canisters of their own. Shortly before 6am, on Hill 70, the order was given to open the valves and a greenish-yellow cloud escaped. The infantry were set to follow it within the hour. Some of the cloud was borne towards the German line but on the left hand side noxious fumes hung over no-man's-land or drifted back in the direction of the advancing troops as the wind altered. This was Sir Douglas Haig's worst fear.

Some troops sought shelter in shell-holes only to find that this was where the chlorine accumulated. The attack seemed to be under threat, but it was now that a 40-year-old piper named Daniel Laidlaw, a Berwickshire man serving with the King's Own Scottish Borderers, came into his own. Mounting the parapet he "coolly marched up and down, giving a stirring rendition of Blue Bonnets Over the Border as the men left the trench", author Robert Hamilton writes in the book.

As Laidlaw himself would recount: "As soon as they showed themselves over the trench top they began to fall fast, but they never wavered, but dashed straight on as I played the old air they all knew, Blue Bonnets over the Border ... I ran forward with them, piping for all I knew, and just as we were getting to the German trenches I was wounded by shrapnel in the left ankle and leg. I was too excited to feel the pain just then, but scrambled along as best I could."

He played another air. "I kept on piping and piping and hobbling after the laddies until I could go no farther, and, seeing that the boys had won the position, I began to get back as best I could ..."

Laidlaw received his VC from the King at Buckingham Palace on February 3, 1916. He even appeared in a couple of movies in the 1920s and 1930s: The Guns of Loos (which featured a young Madeleine Carroll, who would later co-star in Hitchcock's The 39 Steps) and Forgotten Men, playing himself in both. He died in 1950 in Berwick, where he had latterly worked as a sub-postmaster. He was granted a new headstone in 2002, giving him the prominence he deserved as the Piper of Loos.

Another VC Scot, seaman George McKenzie Samson, from Carnoustie, was badly wounded during a daring operation during the landings at Gallipoli, Turkey, on April 25, 1915. He was, in fact. one of six men to earn the Victoria Cross that day.
The problem facing the planners of the landings was how to get a troop-carrying ship on to a well-defended beach without too many casualties. The solution was a converted collier able to carry a drawbridge-type arrangement, which would be lowered once the vessel had been run aground. A steam hopper and three lighters would act as a makeshift pontoon between the mother ship and the shore; the idea was that some 2,000 troops, plus another 1,000 landing in open boats, could establish a beachhead before the Turkish machine-gunners could really get going.

The Trojan ship was the SS River Clyde, which had been assigned V Beach, one of five landing-points around Cape Helles on the tip of the Gallipoli peninsula, but for various reasons the operation did not work as smoothly as had been hoped. Turkish machine-gunners opened up, cutting down many troops as they emerged from the SS River Clyde. Chaos and confusion ensured, and the waters ran red. 

Samson received no fewer than 17 wounds. "Men," he would later recall, "were falling down like ninepins. Perhaps it was only the thought that we must give them a helping hand that made us forget our own danger."

When Samson finally returned home it was to a hero's welcome. One person, however, spotting him dressed in civilian clothes, upbraided him for failing to do his duty for his country – this being a time when white feathers were handed to people who seemed to be dodging their duty.

Samson, despite being troubled by his wounds, joined the Merchant Navy after the war. He died on February 28, 1923, when he contracted double pneumonia while sailing through the Gulf of Mexico.

Lance Corporal William Angus's story bears similarities to Ross Tollerton's. As a young man Carluke-born Angus had signed for Celtic but, unable to establish himself fully, had returned to the amateur game, aged 26, by 1914. When war broke out he signed up for the Highland Light Infantry on the same day as another Carluke man, Lieutenant James Martin.

On the night of June 11, 1915, at Givenchy, France, Martin led a bombing party targeting a German-held embankment but they were spotted and a detonated mine sent them rushing for cover.

Martin was wounded. At dawn on the 12th, he could be seen just beneath the German parapet. It was a very hot day. When he asked for water, a grenade was tossed in his direction.

Angus volunteered to rescue his fellow townsman. His commanding officer gave much thought before permitting a rescue attempt. When he asked Angus if he realised he would almost certainly be killed, Angus replied: "It does not matter much, sir, whether sooner or later." That settled it.

He set off with a rope around his waist and was able to reach Martin and give him some brandy. When he tried to carry Martin back, German fire made things extremely difficult. Angus tried to shield Martin with his body but received 40 injuries.

The two men became separated. Martin was hauled to safety by means of the rope and Angus finally made it via a different route. He lost an eye and part of his right foot. His commanding officer was later moved to remark: "No braver deed has ever been done in all the history of the British Army."

Angus was able to return to an enthusiastic welcome in Carluke, where he became a well-known figure. He and Martin had a close friendship: each year, Martin sent him a telegram to mark the anniversary of his heroism. Martin died in 1956 but his brother continued the tradition.

Angus himself died on June 14, 1959, two days after receiving the final telegram. The wording, as always, read: "Congratulations on the 12th."

Lieutenant Harcus Strachan, originally from Bo'ness, had emigrated to Canada and joined the Canadian Expeditionary Force in 1915. In November 1917, at the Battle of Cambrai, in France, he was with the Fort Garry Horse.

A squadron leader had been killed near the German front line. Strachan took over, urging the squadron through the enemy line of machine-gun posts. With the survivors he led the charge on a German battery, killing seven gunners with his sword. He then rallied his men and fought his way back on foot – and at night – through German lines, bringing with him all his unwounded men and 15 prisoners too.

On the same day and in the same battle, Lance Corporal Robert McBeath, a Highlander serving with the Seaforth Highlanders, single-handedly dealt with a nest of machine-gunners, armed with a Lewis gun and a revolver. Killing one gunner, he attacked other machine-guns with the aid of a tank, pursuing the Germans into a dug-out, shooting the first man who opposed him, and ended up capturing three officers and 30 men.

After the war, McBeath and his wife relocated to Vancouver, British Columbia, and he became a policeman. But he died on October 9, 1922, after he and his beat-partner were shot by a man they had arrested for driving erratically. The partner survived, but McBeath was killed almost instantly.

Victoria Cross Heroes of World War One: 628 Extraordinary Stories of Valour by Robert Hamilton is published by Atlantic Publishing, priced £40.