Like many local lads Tom Allen joined the Territorial Army and served with the Hertfordshire Regiment. He was later transferred to the Royal Berkshire Regiment. On the 4th October 1916, as the Battle of the Somme drew to a close, his Battalion was held in reserve at Authuille Wood and consisted almost entirely of men who had recently joined. The heavy and bitter fighting of the summer battles had cost the Battalion dearly. That morning the Germans attacked the British Trenches near a fortification known as the Schwaben Redoubt, close to the village of Thiepval. It was a fearsome assault with grenades and flamethrowers being heavily employed. Although there was very intense fighting as the British troops battled to regain their positions, which they managed to achieve, the Battalion suffered only two wounded men. Later in the day the area was very heavily shelled by German artillery and a letter from a friend states that Thomas was killed by shellfire whilst on sentry duty. If this is true, then it can be assumed that he was killed after the earlier action of the day.