Thomas was educated at Monkton Combe School, nr. Bath, and at Trinity College, Cambridge, where he graduated M.A. He then studied medicine at the London Hospital, entering in 1898, and qualifying M.R.C.S., L.R.C.P. in 1903. He then held house appointments at Westminster and Poplar Hospitals. Thomas had previously served as a trooper in the Middlesex Yeomanry during the South African War, gaining the Queen’s medal with three clasps. He was in practice at Welford, Rugby, where he was Medical Officer of the Fifth District of the Lutterworth Union, and of the Welford District of the Market Harborough Union, when war broke out. He immediately applied for a commission in the R.A.M.C. He was granted a temporary commission at the rank of lieutenant on 12th September 1914. He then entered the war in France on 30th October, then was attached to the King’s Shropshire Light Infantry as their medical officer the following month.
Early in 1915, Thomas was mentioned in despatches. He was awarded the Military Cross on 6th September 1915 “For conspicuous devotion to duty and energy at Hooge”, and on 31st May 1916 he was awarded the Distinguished Conduct Medal for his actions at Morteldje - “For conspicuous gallantry and devotion to duty. He collected and attended to the wounded under very heavy fire and set a splendid example. Since the commencement of the war he has been conspicuous on all occasions for his personal bravery.” His colonel wrote of his bravery and stated: “He was loved by every man in the regiment.” He was killed on or about the night of 16th September while searching for wounded in front of the enemy wires.
Brigadier-General L Nicholson wrote:- “Dear Mrs Ingram. I cannot tell you how grieved I am to see in the Roll of Honour that your husband had been killed. May I express my deepest sympathy with you in your great bereavement. No more gallant gentleman, or braver soldier ever lived, and his dauntless courage and unfailing cheeriness under all circumstances was worth many men, and the officers and men of his Regiment simply worshiped him. I have lost may friends in this War, but few whom I esteemed more than your husband.” Capt H S Collins, D.S.O., K.S.L.I. also wrote:- Dear Mrs Ingram. I feel I must write and offer you my most heart-felt sympathy on your terrible loss. If there was one, all of us who ever had the honour of knowing him would have given anything to see spared, it was our dear old doc. One could go on forever with his wonderful qualities. I shall look on him as the finest, kindest, most lovable man I ever knew. To say anything about his bravery in superfluous - his two decorations were nothing, for he earned some decoration every time he went into the trenches. But it is as the kindest and most unselfish of friends that I shall always remember him. I feel sure when any of the many officers we have had in the time to come looks back, each one will consider that the bravest and the one he liked best was the doc. Everyone must think that the name we have made is more due to him than anyone - I can’t think how they will get on without him. I am very bad in putting on paper what I think. but hope this and he many letters you will get will be of some consolation to you in your great grief.” Thomas was the eldest son of Thomas Lewis Ingram of The Priory, Wimbledon Common, London; and the husband of Lilian Ingram (eldest daughter of Lt/Col Donnithorne, Royal Scots Greys) of Queen's Cottage, Alexandra Court, Wimbledon, London. They married in 1909 and had two children.