The late Queen had a lifelong obsession with cars that started with her service in the Auxiliary Territorial Service (ATS) during the war.
Princess Elizabeth wanted to serve her country and apparently against the wishes of her father, the King, she joined the Auxiliary Territorial Service (ATS) when she turned 18.
In the ATS she took a driving and vehicle maintenance course in Aldershot, which was usefully near enough to Windsor Castle to make returning home each night possible. She qualified in April 1945, a couple of weeks before her 19th birthday.
After passing the tests she became a 2nd Subaltern and later promoted to Junior Commander. Her duties involved servicing and driving a variety of vehicles as required.
By all accounts she enjoyed her time in the ATS and certainly relished the opportunity to serve the nation just as her fellow countrymen and women were obliged to. However, she did not serve for long as the war ended in May 1945.
As the Queen, Elizabeth remained fascinated by vehicles and enjoyed driving until relatively recently. Diagnosing faults with rough-running engines was a skill she retained throughout her lifetime (although we have no evidence that she ever got on the tools again after the war ended). One of her favourite cars to drive was a Rover P5, of which she owned several examples over the years, two of which she kept and are now in the Heritage Motor Museum in Gaydon.