An Officer and a Gentlewoman: The Making of a Female British Army Officer, By Héloïse Goodley

From grindstone to war zone – the City high-flyer who joined the Army Air Corps

In the mid-noughties, Héloïse Goodley was in her mid-twenties, toiling away at a high-flying City job with all of the associated perks – top salary, big bonuses and 18-hour working days.

"I bought sharp suits, wore power heels, sat finance exams, and spent two hours of my day at the clemency of London Transport on the Underground, commuting to a desk in the shiny glass and chrome of Canary Wharf." It was, she writes, "utterly soul destroying".

Four years into a successful career, after an encouraging conversation with a military man at a dinner party – and with a serious desire to extract herself from the world of the Financial Times, corporate dinners and caffeine – Goodley decided on a major occupational change. Within months, she'd won a place on the officer training course at the Royal Military Academy Sandhurst, and started a new life as an Officer Cadet: "the lowest of the low," as she tells her father. "A worm."

Goodley's book gives an in-the-trenches view of what it's like to transition from a civilian's life to that of a soldier. From the rigours of the physical training and the endless, mindless, disciplining tasks of a super-structured day (four-minute breakfasts, bedding ironed to perfection, litter-collection and loo-cleaning duties, radios continually tuned to Radio 4), Goodley captures the frustrations, agony and boredom, as well as the adrenaline-fuelled highs and the joy of camaraderie.

She describes map reading exercises and war games; training for military engagement during nuclear, biological and chemical warfare by playing rugby in four layers of clothing, rubber gloves and gas masks; and uncovering unexploded bombs from the Second World War while trench-digging in Norfolk armed with spades, picks and Redbull. ("Because in reality the exercise was actually less about our ability to dig a hole in the ground and more a painful experiment in sleep deprivation.")

She survives on contraband chocolate from her granny and by sneaking catnaps under her hat during Sunday chapel. She celebrates the slice of "faux-freedom" every Sunday afternoon when cadets are sent out to run their cars for half an hour to keep the batteries alive: there's a great scene of the Academy grounds full of cadets' cars cruising around at 20 mph, with Goodley driving along singing to her Girls Aloud CD.

There are many telling moments and insights. On her first weekend break, temporarily back in civilian life, she's still questioning her decision, loath to return to the hell of Academy discipline; weeks later, on another break, she's in a bar with friends and realises she's developed a new-found appreciation for Sandhurst and for the Army's merits – including a moral framework that the City lacked. And she doesn't gloss over the "re-engineering" aspects of her experience: researching an essay on leadership, she studies mind-control techniques used by cult leaders, some elements of which – sleep deprivation and fatigue, dress codes, verbal abuse, confusion, and time-sense deprivation – "rang with sinister familiarity".

Less convincing are her assertions that neither she nor her family made the connection between her enlisting and the life-threatening dangers of combat, and that "there is no sexism in the military". But as a published version of the author's prize-winning diary kept during her time at the Academy, the book nonetheless offers an engaging, fly-on-the-wall view of a person developing a new outlook on life.