A moment that changed me: ‘Applying to be a spy felt thrilling – until a stranger approached me on a train’

In 2010 I was 23, and had just moved to London from Manchester, where I had trained as a journalist. I had a dream job – a junior role on a magazine – but it turned out to be quite a miserable place. My manager was open about regretting having hired me and my confidence, which had never been high, plummeted. I was single, my friends were scattered all over the city, and I was renting a basement room with no windows that cost exactly half my monthly salary.

It was on one of these lonely days that a link popped up: MI5 was running a recruitment drive and it sent you to a verbal reasoning test that was part of the application process to become an intelligence officer – a spy, in other words.

Espionage had never occurred to me as a career, and my only thought as I clicked on the link was that it might be a more interesting use of my lunch break than scrolling through Facebook.

I finished the test within the allotted time and went back to work, checking the prices of lipglosses we planned to feature in the magazine, and gave it no more thought until later that afternoon, when I received an email from MI5 inviting me to an assessment centre the next week.

The next few months were a blur of exams and interviews in anonymous London buildings, none of which – for obvious reasons – I was allowed to discuss with anyone. From a distance it seemed like any other graduate recruitment process, but of course it wasn’t. MI5 employees have to be totally open about every aspect of their lives, to protect them against being blackmailed. I was asked about my sexual preferences and for the names of all the people I had ever slept with, and had to hand over bank statements. At one interview, a lock of my hair was cut off to test it for drugs.

It was all surreal, but I didn’t mind. In fact, I found the progressively intrusive hoops I had to jump through strangely comforting: they gave my days and weeks a shape and sense of purpose that had been missing. I had been lost, and it felt as if someone had found me.

I lived in west London at the time, and took the Piccadilly line to work. The train had often come from Heathrow, full of travellers, some of whom could be chatty. So I thought nothing of it when, one morning, the man standing next to me struck up a conversation. He was slightly older, with an accent I couldn’t place and a pleasant but persistent manner.

Whereabouts did I live, he asked. What was it like? How long had I been living there? Was it convenient for my office? Where did I work? I was still instinctively wary: even at 23 I had lived long enough to know that interactions with strange men on public transport, no matter how innocent, rarely ended well.

After a couple of stops, he turned to me as the train slowed to a halt. “Well, this is me,” he said. “It was nice to meet you, Emma Hughes.”

It wasn’t until the train started moving again that I realised I hadn’t told him my surname.

When I got off the train, I stood on the platform, fizzing with adrenaline. Although it was possible he had glanced into my bag, I had nothing easily visible on me that could have told the man my full name. I remembered a friend’s sibling, who had applied for a job with MI6, telling me they had been approached in the street by a man speaking their second language, an unusual one. They suspected it was part of the recruitment process, to test how guarded they were.

Had this man followed me? Had he been told to talk to me on the train to suss me out? What else did he know about me?

For the first time I felt overwhelmingly uneasy: the full force of the loss of agency that signing up to work at MI5 hit me. It sounds ridiculous now, but although I had come round to the idea of watching people for a living, swept up in my escape fantasy I hadn’t given much thought to how it would feel to be watched myself. Or having all my activity monitored, on- and offline, and disclosing every promising new relationship to my employers before we were even official.

This isn’t what you want, a voice in my head whispered. This isn’t the answer.

I never found out who the man was. A couple of weeks later, though, after a final interview, I received a letter from MI5 telling me I had failed my developed vetting – the security clearance required before a job offer. No reason was given, and I was told I couldn’t appeal. It hurt: I felt as if I had been dumped after a whirlwind romance. But deep down, I was relieved.

My life moved on: I got another job, reconnected with old friends, made new ones. I was able to do things I never could have done had I become an intelligence officer: having flings, dyeing my hair loud colours and writing a novel. The person I am now would make an absolutely terrible spy. Whenever I travel on the Piccadilly line I feel overwhelmingly grateful that I got the chance to grow up into her.

• Emma Hughes’s novel, No Such Thing as Perfect, is published by Century, £12.99