Mary worked at the Co-op for four years before being called up in 1943. She had to go to Scotland to do her training, which she said was an event in itself. She had only once been to Scotland before, and that was when she went on a school trip to Edinburgh. Mary's journey involved her getting a train to Glasgow, changing trains there for the onward journey to Bewick, which was on the banks of Lock Lomond.

Mary's stay in Scotland was in December and January. She recalled what a beautiful place it was. Unfortunately for her and her fellow Wrens, it being winter, they had to go round in oilskins, clogs and sou'westers. Apparently the site had once been an American Naval Base with just Nissan Huts and oil stoves to keep them warm. Mary said it was dreadful and she would never forget the experience as long as she lived.

After her training in Scotland Mary was sent Rochester, which was not far from the Chatham Dockyards. She had all her injections and what not done there. As a young Wren, Mary remembers, the Royal Navy being very protective towards the young girls who were stationed there. If they went into Chatham and were caught by the MP's loitering, talking to anyone, more so Naval Personnel, they were in front of the Commodore the next day.

Mary was not in Chatham very long before moving to Staines in Middlesex. Here she worked in a former Lino Factory, which the Royal Navy had taken over. There were Men Ratings as well as the Wrens, working in the various departments, shipping, packing and office jobs; this was where Mary worked. From this factory the Navy were repairing and supplying spare parts and machinery for the ships including anchors and propellers which were then transported to Naval Bases abroad.

When in Rochester, Mary's accommodation was quite good. She and her fellow Wrens lived in one of the houses taken over by the Admiralty. There were four streets of Victorian houses, which were on two floors with attics and large cellars. They also had small gardens to front and back of the house. The Windows were blacked out on the inside and sandbagged half way up the windows on the outside. Mary and her fellow mates saw at first hand the raids in London, all the bombing and the doodlebugs. It was a terrible experienced she said.

In the house at Rochester, the Wrens, lived, slept, and washed. There was no furniture, only makeshift cupboards for clothes with curtains around them. No food was taken there as meals were served in the canteen at the Wrens quarters in Rochester. One or two Wrens were billeted there, but it was just a staging post before being transferred.

Mary was at Chatham about eighteen months before she went to Windsor. She and a number of her fellow Wrens actually lived in Clewer Park, a large house which stood in its own grounds, with the house backing onto the River Thames and Windsor Racecourse. Whilst in Windsor Mary was a messenger for the Navy and she used to go to The Admiralty in Trafalgar Square to deliver messages.

She used to get a pass to take her on the train from Staines to Windsor, where there was a civil defence place. This was all to do with the Admiralty. It was like the military supplies department. When signals came up from the Admiralty, into the teleprinter room she would deliver them to the different departments. She was one of the first in the section, apart from the Admiralty, to know that the Second World War had ended.

Mary came out of the Wrens in January 1946 after being with the Wrens just over two years. She never thought she would have been called up for the war. Her position as Wren Caygill was, in her opinion, just an ordinary jenny Wren who was a messenger.