“Were you with anyone else this morning on the train?” the police sergeant asked over the crackle of the phone line.

“No, just me,” I replied.

Well, just me and all the other sleepy commuters in our carriage, outbound on the 08:36 from Clapham Junction to Teddington, but I knew what he was asking.“Because someone else called up and reported the incident this morning too.”

Interesting, I wondered who that had been? Perhaps the older lady sitting in the four-seater who had offered the young woman some chewing gum? Or maybe the dark haired woman who, at one point, had offered support during the bizarre situation, saying: “This doesn’t seem right.”

The details of the other commuters on the train felt rather blurry now, the man and the young woman, on the other hand – they felt burned into my brain.

“White, male, overweight, sweating profusely through his light blue shirt”, was how I had described the man to the London Transport Police over the phone six hours earlier. “I would guess: maybe late fifties, his white hair was slicked back and he was wearing glasses – sunglasses, so I couldn't actually see his eyes.”

“And the young woman?” the police officer had asked. “She was wearing polka-dotted denim jeans and a plain white top, canvas shoes and holding a pink-ish-orange handbag.”

“She looked really plain. No, not dressed like a prostitute.” I restated to the Sergeant.

“If you find the CCTV footage, I’m the one wearing a tight black skirt and leather jacket.” I probably looked more ‘promiscuous’ than she had, but I didn’t say that to the sergeant. After all, I am allowed to dress sexy right? #feminist

I really hoped that they did find the CCTV footage. I wanted to know what had happened to the young woman. Was she okay? Had she found safety? Where was she now? These questions had been buzzing around my head all day. I was less curious about the fate of the man, but I prayed that the police found him and arrested him.

That morning I had been exposed to a new world, one which I knew theoretically existed but up until this point hadn’t popped my middle-class South West London bubble.

But there it was, not down some back alleyway, not a tragic story from the slums of India, and not glamourised in a film starring Liam Neeson. It was here, barely hidden below the surface – the world of human trafficking. Pop!

My morning commute had started like any other Friday – fuelled by a lack of sleep or perhaps not enough caffeine. I watched with weary eyes as a train pulled into the platform opposite. A fellow woman commuter was asleep, her head pressed against the train window. Bless her, I thought, eagerly waiting for my own train to arrive so I could do my best job of imitating her.

“The train now approaching platform eleven is the 08:36 to Teddington, calling at Earlsfield, Wimbledon, Raynes Park, New Malden…” announced the God-like South West Trains automated voice over the tannoy.

Moving towards my train, for some reason I decided to step onto the carriage one further up from my usual spot. A young woman blocked my way. She was clearly unsure as to whether this was, in fact, the train she was wanting to catch. As she continued to step on and off the train, the man with her did the same.“I think this is the wrong train,” he said to her as the two of them ended up on the train as the doors closed. She didn’t reply as she sat down in one of the four-seaters.

The train was quite full, but I found a seat in another four-seater across the aisle. The man who I assumed was her father remained standing.“We need to get to Guildford. This train doesn’t go to Guildford,” he continued.I pulled out my phone and was just about to escape into Instagram-land (a favourite morning tradition), but something stopped me. There was something strange about their interaction. The young woman had still not replied. Were they having an argument about how to get to Guildford? Perhaps she was ignoring him – a tactic I have definitely used with my own father before. She looked a bit younger than me and the man a bit younger than my father, but this didn’t feel like a typical father/daughter spat. She didn’t look frustrated, embarrassed or upset.

Remembering the unspoken London Code of Conduct for Keeping to Yourself while Travelling on Public Transport (LCCKYTPT), I decided to break Article 4 and make conversation with a complete stranger. #rebel. Leaning towards her, I asked: “Where are you trying to get to?” She murmured an answer I couldn’t quite hear so I stood up (breaking many more unspoken personal space rules) and moved to the seat behind her.“I’m going to the doctor. I have the flu. And there’s a train strike,” she repeated. This caught me off guard, not because of what she had said but because she had spoken in very broken English and with a thick Eastern-European accent.

In the meantime, the man had sat down across from her in the four-seater. Thinking quickly, I regained my composure.“Okay you have the flu, and who is he?” I asked indicating toward the man.“I’m her father,” the man answered on her behalf... in perfect Queen’s English and British accent. ‘Liar’ my inner-voice shouted as my heart rate increased. He was definitely NOT her father. “Oh right, okay” I replied in a way which I hoped convinced him I believed him. Dreams of falling asleep against the train window had long since gone. I was 100% awake now. I wondered if anyone could hear my brain whirring.

Looking around everyone else was dutifully following the LCCKYTPT (not my best acronym I confess) but clearly eavesdropping on our conversation. South West Trains broke the momentary silence: “The next stop is Earlsfield.” “We can change here and get the train to Guildford,” the man informed the young woman. He stood up and made towards the carriage doors. The young woman, however, remained seated. “You know there will be trouble if we don’t make it to Guildford,” he addressed (lightly threatening) her again.

The train pulled into Earlsfield and the doors made the alarm sound indicating they were ready to be open. Coaxing her some more the young woman stood up, but instead of moving towards to the doors she sat back down in a different seat. The alarm bells for the train doors went off again indicating this time that they were locking ready for departure. Another set of alarm bells went off – in my head. One thing was clear: whatever the relationship between these two, she did not want to go with this man wherever he was going.

The man started talking to someone on his phone and I took the opportunity to pray. Jesus, I don’t know what’s going on here but give me courage, courage to do whatever you need me to do. Feeling incredibly helpless I took stock of the situation. The young woman was avoiding eye contact. She wasn’t upset or flustered. There was no sign of physical injuries. She just looked empty. She wasn't holding a phone or wallet but she did have a small handbag. Her clothes looked plain and she wasn’t wearing any makeup. I looked back at the man. In his phone case, which was still pressed to his ear, I could see multiple train tickets: the only other thing he had with him was an iPad.

Despite it being a rather cold August morning, I noticed he was sweating profusely through his shirt. He reminded me of a car salesman. That thought made my stomach feel sick. South West Trains made me jump: “The next stop is Wimbledon.” Again the same situation unfolded, the man tried to coax the young woman off the train. Again she stood up making to leave with the man. And again she sat back down as the doors closed. Jesus, I don’t know what to do, give me courage. Why is no one else doing anything? Where are the adults?

There was no sign of the train guard or any guards on the platform. “Are you okay?” I asked the young woman widening my eyes trying to communicate something deeper with my question. She opened her mouth and shut it again, as though she was either struggling to remember the English or not sure how to phrase what she wanted to say. With my back towards the man, I mouthed to the young woman and pointed to my phone: "I can call someone for you?"

“The next stop is Raynes Park.” I realised Raynes Park was their last chance to switch directly to a Guildford train. The man was getting more frustrated now. The same scenario played out again. He was being careful not to get physical with her. This time I stood up in-between the two of them. Jesus, give me Kingdom courage. The doors opened. The doors shut. “You don’t have to go with this man.” I was no longer pretending he was her father.“I can go with you. The next stop is New Malden." The doors opened. She stood up. This time she stepped off the train. The man stepped off the train. I had no plan.

Literally no idea how to help this young woman. Guess I might be a bit late for work, I thought, stepping off the train behind them...One of my absolute favourite quotes of all time is from Rick Warren: “The most dangerous prayer you can pray is this: 'Use me'”. I believe God calls us to step out in faith into uncomfortable, unfamiliar and dark situations and when we do we can expect him to use us. Obviously much easier said than done!

That morning I took a step of faith, but his story is not meant to be about me. A much braver young woman stepped off the train that morning. Now, where were we …The three of us walked in convoy along the platform one behind the other. The young woman walked up to the next carriage of the train we had left and to my surprise, she stepped back on. The man followed her, I followed him. Sensing my presence behind him he turned around. I swallowed hard.“Why are you following us?” He asked with indignation ringing in every word. I didn’t answer. Instead, my eyes moved from his and continued to follow the young woman who had made it to the next set of doors.

The alarm for the doors went and in that split second with the man distracted, she stepped back off the train! The man, following my gaze, moved swiftly towards the shut doors. Pushing the button he tried to get them to open again. Too late, they were locked. He turned back towards me. I froze. From across the heads of the sleepy commuters, we stared daggers at each other. Inside my chest, my heart was beating faster and faster. The train started to pick up speed too. He turned and walked through the door into the next carriage. He was gone.

I let out a deep breath. Jesus, we won!

Jessie Boston works for Justice and Care, an anti-modern slavery charity. Find out more about Justice and Care @justiceandcare

If you think you have witnessed anything related to human trafficking or modern slavery call the Modern Slavery Helpline on 0800 0121 700 or visit www.modernslaveryhelpline.org