Will was walking over Westminster Bridge in London when a car crashed into him from behind. He didn't know it, but he'd been caught up in a terror attack that killed five people and injured 50. In the chaos that followed a stranger looked after him. But then they were separated and he could only remember her face...
Will is stressed. He's due to meet the team he'll be working with at his new job and he's running late. He's taken extra care with his outfit today, wearing smart jeans and his favourite brown suede shoes. As he rushes down the road he decides the quickest route will be to take the Jubilee Line from Westminster underground station. He walks on to Westminster Bridge and starts to cross the Thames towards Parliament.
Cristina is in a pound shop picking up cleaning products. She's just come from a talk about the economies of developing nations - a topic she became interested in while volunteering in China and Myanmar.
Placing her purchases in her bike basket, she decides to head home via Westminster Bridge. It's a little out of her way but Cristina considers it the prettiest bridge in London. She pushes off from the kerb and merges into the traffic.
There are a lot of tourists on the north side of the bridge so Will crosses to the other side where he can walk faster. He sprays deodorant under his shirt as he goes. It's a miserable March day and he curses as it starts to rain. He suddenly hears a car accelerating loudly behind him. He has the sensation of being propelled forward, before everything goes dark.
Cristina thinks nothing of the heavy traffic but then she hears screams. She sees people streaming off the bridge and a passer-by tells her to turn back as there has been a terrible accident. Instead she parks her bike and continues on foot. She has basic nursing training and thinks she can help.
She reaches a young man in brown shoes lying on the wet road with another man hovering over him. She asks if there is anything she can do.
"Please can you take over? I need to leave," the man on his feet replies, clearly agitated.
Cristina agrees and kneels down. She takes the injured man's hand and asks his name.
"It's amazing how our friendship came out of something so horrific and terrible," Will says.
"We wouldn't ordinarily have crossed paths. We're different ages, have different professions and live and work in different areas."
It's a year later and he's sitting with Cristina at the back of a busy brasserie in Soho. The sun is streaming through the windows and on the street outside office workers are mingling and sipping their first post-work pints.
Both have just come from work - Will, 25, from his job rejuvenating the area around Baker Street and Cristina, 34, from a meeting with an advertising firm. While Will grew up in London, Cristina moved to the city from Portugal 12 years ago.
It was an act of terror by Khalid Masood that brought them to the same place at the same time. On 22 March 2017, he drove a hired car into dozens of pedestrians on Westminster Bridge and stabbed to death an unarmed police officer, before being shot and killed himself.
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Will believes he was the second person to be struck by Masood's car. He woke up to find himself lying in a wet gutter.
"I had a strong sensation of pain all over my body," he says.
"I could see the London Eye and County Hall from where I was and I could hear a lot of panic and distress but I wasn't really aware of what it was about."
Cristina came across Will just a few minutes later.
"Will didn't look badly injured but he was very confused. He was panicking because he had to go somewhere but he couldn't remember where," she says.
"I held him and hugged him and tried to keep him calm by asking him lots of questions. We were sitting on the kerb watching this awful scene, having a mundane conversation about his parents and his job."
They waited as the paramedics dealt with the most urgent cases. Will had scrapes down his back and a mass of bruises down his leg and was taken to hospital in the last ambulance that left the bridge. There was no room for Cristina.
"I terribly wanted to go with him, but I knew it wasn't my place as there was a young policeman, Special Constable Thomson, with him," she says.
"Due to the chaos, no-one had asked me for my details, so I simply walked off the bridge."
Cristina continued to believe it was an accident until she called her boyfriend. He told her it had been a terrorist attack and that she should head home.
Cycling back to her empty flat, she called Will's firm to explain what had happened.
"I knew lots about him so I then tracked him down on Facebook and left a message saying, 'I hope you're OK, let me know.'
"I think I was in a state of shock. It was like going through a violent 3D movie. I didn't feel like going out again so I stayed at home that evening."
Meanwhile, Will's condition began to worsen. As a lower-priority case he was left to sit in A&E as medics rushed around him. Then he began to feel nauseous.
"My speech started to go strange. I was trying to say things and the wrong word would come out. They put me in a wheelchair and I started throwing up. Every time they tried to lay me down I'd be sick."
When police officers came to take away his clothes and bag, he tried to ask to keep his phone but struggled to express himself. The doctors began to seem concerned. Following X-rays and CT scans he was put in a head brace.
"The hospital staff had a sense of urgency and I thought, 'Oh God what if I don't come through this?'"
Due to the brace he could only see the ceiling. He remembers his parents arriving and having to peer over his trolley for him to see their faces.
Will was diagnosed with a carotid artery dissection - a tear in one of the arteries in his neck had allowed blood to enter the artery wall and split its layers, forming a blood clot. He was given medication to thin his blood and reduce his risk of having a stroke.
"I just wanted to sleep so I could just pretend it hadn't happened, but I couldn't, mainly because of the pain," he says.
In the following days Cristina tried to put her experience behind her. She only told a few friends who asked her why she looked shaken. But she didn't tell her mother in Portugal because she didn't want to worry her. She also chose to keep it from her colleagues.
"There was nothing to tell," she says.
"I couldn't relate what had happened to me to this big national event."
In the weeks following the attack Cristina continued to cycle around London. However, she found that she felt on edge and anxious if a car passed close by.
"I went through a phase where I would do an assessment of whether the road might be suitable for an attack," she says.
However, she felt strangely calm when she crossed Westminster Bridge again.
"I think it's because I thought an attack wouldn't happen in the same place twice."
Cristina hadn't heard from Will but assumed he would get back to her when he was ready. She didn't know that he was actively trying to find her.
In hospital Will slowly regained his ability to walk. He was aware that people were talking about Westminster Bridge in hushed voices. He asked the hospital psychologist for details and he suggested they go through a newspaper article with Will's father.
"My dad summarised it for me and said what the pictures showed. I didn't really think about the driver, I just felt very overwhelmed by the scale of it all," he says.
Will's memory of the bridge was hazy. However, he remembered that a woman had looked after him and he wanted to track her down to thank her.
"I thought she might be Spanish and I knew she had good teeth because I remember her smiling a lot.
"So the police were going through the witness statements to find someone like that!"
After a week in hospital Will moved back in with his parents. He was given his sister's room as it had a "nice double bed", while she moved to his old box room.
"It was quite intense," he says.
"I'd moved away from home when I was 18 and was very independent. It was difficult to be looked after and have decisions made for me."
Will wanted to get better as quickly as possible. He had several appointments most days, visiting the hospital and meeting with a counsellor, the Victim Support charity and police liaison officers.
He needed to nap during the day due to the extreme exhaustion brought on by his head injuries.
"I felt dizzy a lot of the time, my eating was on and off and I wasn't sleeping much at night because my neck was so painful," he says.
"I had to take breaks from other people as well. People were obviously concerned and wanted to know what happened but I ended up repeating a sort of script."
Friends and neighbours left food at the door, which Will found touching but also overwhelming.
"I just don't like attention," he says, shifting in his chair.
Soon after moving home Will was invited to a service at Westminster Abbey for everyone who had been involved in the attack. Afterwards he decided to walk across the bridge with his family.
"It was a normal day with lots of tourists everywhere and people going about their business. You couldn't really tell what had happened, although there were barriers up.
"It was strange as I didn't really feel like I had been there, as I couldn't remember very much."
A month after the attack, Will was disappointed to learn that the police hadn't found the woman who helped him. But the next day while checking Facebook, he spotted some messages from people not on his contacts list.
"I had one from a cousin and then I came across a message from Cristina that basically said, 'You won't remember me but I helped you on Westminster Bridge. Please let me know you're OK.'
"I ran - well I hobbled - down the stairs and I read it to my mum and dad but I couldn't finish it. They were both in tears."
Will responded straight away and they arranged to meet.
"It was so strange," Cristina says, in the brasserie where their reunion had taken place a year earlier. "I felt very close to Will but he didn't really remember our conversation."
"I recognised her straight away," Will says. "And we hugged - Cristina is a real hugger."
Will had brought a map so Cristina could point out where she found him and take him through what happened.
He also gave her a card from his mother, thanking her for staying and looking after him on the bridge.
"It really helped my family to know that someone had looked after me when they couldn't," Will says.
Over the following weeks they continued to meet for coffee. At first Will wanted to know some more details about the attack but slowly their chats turned to what was going on in their lives.
"How do you become friends with a person? I think we think about things in a similar way," Will says.
"It was very natural," agrees Cristina.
"We'd meet to check in with how he was and then we'd talk about how I was. We were both going through big things."
Cristina ended her long-term relationship with her boyfriend, while Will started his new job and moved back in with his flatmates.
"There isn't any manual for how to move on after a terrorist attack," Will says.
"I just went with my gut as I wanted to regain control of my life. I didn't want to sit at home feeling sad about what had happened and frustrated that I couldn't do any exercise."
However, the transition was more difficult than he had expected and he found he was less confident about making decisions.
"I felt very up and down. There were moments I felt terrible but then also moments when I felt really empowered," he says.
Through it all he knew he could talk to Cristina.
"It was really helpful during a time when I felt crap about what had happened to have someone who had seen me at my worst," he says.
"She wasn't cautious with me at all and was very honest. If I said something very melancholy she'd get me to consider other things."
Cristina adds: "It also gave me a trusting space to talk."
As the months passed, Will's medication was reduced and his appointments became less frequent. He finished trauma therapy but continued to see an NHS counsellor once a month.
"I was thinking about it [the attack] less and it was becoming less significant," says Will. "Until something happened that reminded me of it."
In November, he was in a taxi with a colleague just off Oxford Street when he saw panic-stricken people running past the car. They got out and sought shelter in an office reception.
After half an hour and with little information to go on they decided to join their colleagues in a nearby hotel.
"We crossed Oxford Street and it was completely deserted. Everyone was locked in shops."
They reached the hotel where a back room had been set up with food for them and people evacuated from Selfridges. Will then realised he was experiencing a fight-or-flight response.
"I had difficulty breathing, my hands and arms went numb, I couldn't stand up as my legs were just jelly. Eventually my panic came down but it left me exhausted."
The panic had been caused by rumours of a gunman on the loose. This turned out to be a false alarm, but it still had an effect on Will.
"I took a week off work to recover," he says.
"You made yourself go back to Oxford Street," Cristina prompts.
"That's right. I went once during the day when it was a bit quieter," he agrees.
Last month, Will received the upsetting news that he still can't return to swimming, jogging or cycling - all activities he enjoyed before the attack. Doctors say vigorous activity could damage his carotid artery, which is still healing.
"I do get angry, I have moments of frustration that I'm still not better," he says.
"But I do think I've done a lot of growing. I have a greater perspective on what's important in my life and I don't worry so much about what other people think."
Cristina says: "I feel privileged to have been around him this year.
"Will's a really generous and sensitive person and very open to the world. Meeting him marked a new caring way of being in my life."
The two of them catch up in person every few weeks.
"Cristina is very strong and supportive. She's just a genuinely lovely person," Will says, meeting her gaze.
"A friend of my mum was talking to her recently about people have angels. She thinks you were an angel for me that day.
"I'm very happy you chose to walk on to the bridge."
Follow Claire Bates on Twitter @batesybates
Georgia Catt (@georgiajcatt) interviewed Will and Cristina for The Untold, on BBC Radio 4.
Family photos courtesy of Will Dyson.
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