On January 14, 2008, Jonny Benjamin and Neil Laybourn met for the first time on Waterloo Bridge: the former in such despair he was ready to jump, and the latter the unexpected good Samaritan who intervened.
With a promise that “things can get better” and an invitation for coffee, Neil successfully talked Jonny back to safety before they went their separate ways.
Eight years later, thanks to a nationwide social media campaign to “Find Mike” - Jonny’s nickname for the man who saved his life - the pair were reunited in an extraordinary moment in the public eye.
On Sunday they will run 26.2 miles along the streets of London together, as they take on the challenge of a lifetime in aid of mental health charity Heads Together.
Jonny, 30, and Neil, 34, are among the remarkable cohort of runners invited by the Duke and Duchess of Cambridge and Prince Harry to take on the London Marathon for their personal cause.
They resolved to take on the race while on the train together last year, on their way to a Heads Together event with the Royals as they, in their own words, got “swept away in the moment”.
Neither have run a marathon before. They are on track to raise £50,000 for Heads Together.
The last week, they said, has been “phenomenal”, as they admit crossing the finish line on Sunday will be “very emotional”.
Jonny, who was diagnosed with schizoaffective disorder when he was 20, has spoken frankly about his own mental health struggles, which culminated in him standing on Waterloo Bridge contemplating suicide.
Neil, who spotted the lone figure of a young man standing still amid the commuters while walking to work, stopped to talk to him, telling him: “It'll get better mate, you will get better."
After a 25 minute conversation, the emergency services stepped in and the pair were swept away and back to their respective lives.
It was only in 2014, when Jonny launched a social media campaign to find and thank the stranger, that they were reunited.
The pair, who both live in London, are now firm friends, campaigning jointly on mental health issues and buoying one another up through their gruelling marathon training.
“It’s going to be emotional, very emotional,” Jonny said of Sunday’s run. “But we’re all in it together and I’m excited to be a part of it - it’s a privilege.”
“I’m feeling really positive about it,” Neil added. “When you’ve said it, and you’ve told Heads Together you’re doing it, you can’t undo it then.”
The last week, they said, has seen a “tidal wave” of awareness on mental health issues, after Prince Harry and the Duke of Cambridge spoke frankly about their own struggles following the death of their mother.
Charities have already reported calls and hits to their website nearly doubling in the wake of the Royals’ efforts, Significantly, Twitter reported a 16-fold rise in conversation about Prince Harry and 23-fold about Heads Together the day after Prince Harry’s Telegraph interview, with conversation widening out on day two to people discussing all aspects of mental health.
“When I walked past Jonny that day on the bridge, there was a fraction of anything about mental health in the media,” said Neil.
“Now, there is an article in the newspaper every single day. It’s like an awakening at the moment, and it’s so great to see that.
“Being part of Heads Together with Jonny, it’s a really nice time of our lives together where we can try and push that message out there.”
On the Royals, he added: “They’ve got a lot on their shoulders, and to be open and honest about something which has so much stigma about it is really commendable.”
Jonny, who has gallantly told his friend to run ahead of him tomorrow after suffering a series of setbacks and bereavements which have disrupted his training, said: “The last week has been phenomenal, the way that people are talking about it. Everyone’s talking about it, it’s amazing and to be part of it is a real privilege.
“I hid what was going on from my family and friends, and I think if these conversations had been the norm back then I would have been more open for sure.”
But he added, it was essential for mental health services to be able to provide the help for people who do speak out.
“It can’t just be us talking, it’s got to be more from the top,” he said.
The pair will join the Telegraph’s Bryony Gordon in running for Heads Together, along with broadcaster Sian Williams, Radio 1 DJ Adele Roberts, Maddy Austin, the daughter of newsreader Mark Austin who has spoken candidly about her anorexia.
700 people will run officially for Heads Together, with the remaining 39,000 London Marathon runners being offered the charity’s distinctive blue headbands to wear alongside their own causes.
Prince Harry and the Duke and Duchess of Cambridge will attend various sections of the route to cheer runners on, with the Prince telling them: “I’m sure it will be one of the most rewarding experiences of your life. William, Catherine and I will be there to cheer you all on.”
Now, the young Royals have pledged to continue supporting the mental health cause, with the millions of pounds raised for Heads Together to be ploughed into real, tangible support for the public.
A spokesman for Kensington Palace said: “The Duke and Duchess and Prince Harry have decided that the work of Heads Together will continue well past the marathon.
“Their Royal Foundation will be partnering with the voluntary sector to back new initiatives to help people have conversations and get the information and guidance they need.
“This will include new digital programmes and a major push on research and training.”