Paul Fussell, in The Great War and Modern Memory, explains:

One way of showing the sporting spirit was to kick a football toward the enemy lines while attacking. This feat was first performed by the 1st Battalion of the 18th London Regiment at Loos in 1915 It soon achieved the status of a conventional act of bravado and was ultimately exported far beyond the Western Front. Arthur ("Bosky") Burton, who took part in an attack on the Turkish lines near Beersheba in November, 1917, proudly reported home: "One of the men had a football. How it came there goodness knows. Anyway we kicked off and rushed the first [Turkish] guns, dribbling the ball With us." But the most famous football episode was Captain W. P. Nevill's achievement at the Somme attack. Captain Nevill, a company commander in the 8th East Surreys, bought four footballs, one for each platoon, during his last London leave before the attack. He offered a prize to the platoon which, at the jump-off, first kicked its football up to the German front line. Although J. R. Ackerley remembered Nevill as "the battalion buffoon," he may have been shrewder than he looked: his little sporting contest did have the effect of persuading his men that the attack was going to be, as the staff had been insisting, a walkover. A survivor observing from a short distance away recalls zero hour:

As the gun-fire died away I saw an infantry man climb onto the parapet into No Man's Land, beckoning others to follow [Doubtless Captain Nevill or one of his platoon commanders.] As he did So he kicked off a football. A good kick. 'The ball rose and travelled well towards the German line. That seemed to be the signal to advance.

Captain Nevill was killed instantly. Two of the footballs are preserved today in English museums.

That Captain Nevill's sporting feat was felt to derive from the literary inspiration of [Henry Newbolt's] poem ["Vitai Lampada"] about the cricket-boy hero seems apparent from the poem by one "Touchstone" written to celebrate it. This appears on the border of an undated field concert program preserved in the Imperial War Museum:

THE GAME

A Company of the East Surrey Regiment is reported to have dribbled four footballs-the gift of their Captain, who fell in the fight-for a mile and a quarter into the enemy trenches.

On through the hail of slaughter,
Where gallant comrades Fall,
Where blood is poured like water,
They drive the trickling ball.
The fear of death before them
Is but an empty name.
True to the land that bore them-
The SURREYS play the game.

And so on for two more stanzas. If anyone at the time thought Captain Nevill's act preposterous, no one said so. The nearest thing to such an attitude is a reference in the humorous trench newspaper The Wipers Times (Sept. 8, 1917), but even here the target of satire is not so much the act of Captain Nevill as the rhetoric of William Beach Thomas, who served as the Daily Mail's notoriously fatuous war correspondent. As the famous correspondent "'Teech Bomas," he is made to say of Nevill's attack: "On they came kicking footballs, and so completely puzzled the Potsdammers. With one last kick they were amoungst them with the bayonet, and although the Berliners battled bravely for a while, they kameraded with the best." (The Great War and Modern Memory, 27-28.)