With his parents in India, Jimmy ran away from school in 1912 to join the Royal Artillery as a trumpeter.
When war was declared, the 16-year-old forged his father’s signature to get to France. In July 1917, aged 19, he was 2nd Lieutenant to a commander in charge of 19 gigantic mines detonated under Messines Ridge as a prelude to Passchendaele.
The 7 June blast, the largest non-nuclear explosion in history, killed 10,000 enemy troops. Jimmy said:
“The earth seemed to tear apart right in front of us. It was an extraordinary sight. The whole ground went up and came down again. Like a huge mushroom. I can see it now! It was tremendous. One almost felt ‘Good old England’. You wanted to wave a little Union Jack. Thank God we’ve done something.”
Jimmy was hit by shrapnel after going over the top in a team of Royal Artillery observers. He lay unconscious for hours before finding he could walk. After 18 pieces of shrapnel were removed from his head, a Royal Army Medical Corps colonel told him:
“There’s a thing here called the medical comforts chest and a colonel is allowed to open it and give a chap anything he asks for, so what would you like? Anything sir? Anything, old chap I’d love a bottle of Guinness, sir Then you shall have it”
Jimmy had been in the Ypres Salient since October 1916, facing the enemy from three sides.
“I came to hate that salient. Absolutely loathed it. The names were so sinister – Zonnebeke, Hill 60, Zillebeke – they terrified you before you got there. To end up making for Passchendaele was the last straw.
“The salient wore you down. The weather, the lack of rations, everything seemed to be against you. You were wet through for days on end. We never thought we’d get out alive. You couldn't see the cloud with the silver lining. There wasn’t one.”
Then there was the deadly mud.
“On the day I reached my lowest ebb I’d gone to meet the ammunition wagon. A heavy shell burst very close. The six horses pulling that wagon took fright, veered off the road and down they went into the mud. We had no possible way of getting them out. They sank so fast that we had no chance even to cut them loose from the wagon. We managed to get the drivers off but the poor horses just sank faster and faster and drowned before our eyes. They disappeared within minutes.
“One of the drivers was absolutely incoherent with terror. It was the thought of being drowned in that awful stuff. It’s a horrible thought. Anyone would rather be shot and know nothing about it.
“That incident depressed me more than anything else in the war. I just felt: ‘What the hell’s the use of going on? I don't care a damn who wins this war.’ It was a nightmare. I have it still.”
Jimmy rose to Lieutenant Colonel after the war. In 1941 he was in charge of anti-aircraft battery training in Oswestry, Shropshire, when his junior commander mentioned one of the recruits was a “Free French girl”. Intrigued, Jimmy asked to meet her. She was Violet Szabo, who became a legendary secret agent in France.