When the war began, Jack was working as a shipwright in the Lowestoft shipbuilding yards. His job was classified as a reserved occupation as he was involved in the construction and fitting out of the first wooden mine sweeper for the Royal Navy. Because he could not join the regular armed forces he joined the LDV (Local Defence Volunteers), soon to be called the Home Guard, when they started up and was trained by them as a medic.
 
It was during the time he was working on the ships that Jack had his most frightening experience. The men could not stop work for every air raid warning, so aircraft spotters were placed around the yard and if a German bomber was spotted heading towards them, a ‘Crash Bell’ was sounded and the men downed tools and headed for the shelters. One of the shelters near Jack’s place of work was a three-bay above ground shelter which he and a large number of other men used. During one raid this took a near miss from a German bomb and as the blast entered the shelter, he was picked up and flung up the far end. He was the only man to survive in his part of the shelter.
 
In 1942 Jack was sent down to London to act as a Waterman on the Thames but instead ended up working on the Mulberry Project.
 
After the war Jack joined the British Red Cross and did his training at Easingwold. A lot of this was for managing a disaster area after a nuclear attack, including how to manage the local population and the supply of food in the area. He also learnt how and who to select for evacuation after a nuclear attack, which greatly upset him as he would have had to choose who lived and who died. During the 1970s and 80s he planned and took part in a number of disaster exercises with all the emergency services and the Army in and around Cambridge.