When
the war started in 1914 Tom joined the 2nd battalion of the South Wales
Borderers and saw action in Gallipoli where he was wounded. Once he and his
unit were evacuated from Turkey, they were sent to northern France and were
soon pushed into the front line. He was home on leave in June 1916, when he
reported that he was quite well and there were more opportunities to sleep
away from the front line in France than in Gallipoli. The Somme offensive
began once he returned to the front line in August and continued into
autumn. Then in October Tom’s family received news, which was later reported
in the Brecon and Radnor Express of 19th October 1916: 
We
deeply regret to announce the death of Pte. Tom Williams, S.W.B., son of Mr
and Mrs Williams, Cwmdu, which took place on the 3rd inst. in France. He was
24 and had been through the Gallipoli campaign and slightly wounded. A shell
burst near him on the morning in question with almost instantaneous fatal
results to Williams and a comrade. Williams is spoken very highly of by the
officer who communicated the sad news to his parents. Deep sympathy is felt
for them. A short time later on the 9th November, the B&R carried the following report:
The memorial service at Maesyronnen, in commemoration of the death of Pte. Tom Williams, S.W.B., whilst fighting for his king and country in France last month was very largely attended. The old edifice was filled with a devout and attentive congregation, who assembled to pay their tribute of respect to the young soldier and his family, who were all members of the church at Maesyronnen. The parents, Mr and Mrs Williams (Cwmdu) and the children, including Pte. George Williams, K.S.L.I. (brother of the deceased, on leave from Shrewsbury) and other near relations, formed the mourners. The service, which was most impressive, was conducted by Rev. W. Jones (pastor), who spoke words of consolation and hope to the bereaved. The departed was only 24 years old, and, said the minister, “Greater love hath no man than this, that a man lay down his life for his friends.” Special hymns were sung, Mr Roger Prosser presiding at the organ
Tom was buried in the military cemetery at Vlamertinghe in southern Belgium next to his comrade. Whilst Tom’s grave may not be here at Maesyronnen, he is with us every week - his name is on a small brass plaque on one of the benches, along with the name of our other war casualty William Edward Jones who died in 1918