A man who was dissauded from trying to kill himself has launched an internet campaign to find the man, known only as "Mike", who talked him out of it.
Jonny Benjamin was about to jump to his death off Waterloo Bridge when a passerby stopped him and talked him down.
Benjamin, who suffers from schizoaffective disorder, had climbed over the railings and was about to throw himself into the Thames.
He has taken to Twitter to try to find the good Samaritan to say thank you to him.
Benjamin now works as a mental health campaigner and is making a film of his recovery. His quest is being backed by mental health charity Rethink.
He said: "His act of kindness changed my outlook on life and I have thought about him ever since.
"I want to find this man so I can thank him for what he did. If it wasn't for him, I probably wouldn't be here today."
Benjamin recalled how the commuter, who he described as being in his early twenties, offered to buy him a coffee.
"He was very calm. He said: 'Please don't do this, I've been where you are and you can get better. Let's have a coffee and we can talk about this.'
"He reminded me of what people do every day so the normality of it was really inviting."
Benjamin climbed back over the railings to safety, where he was seized by police. He never found out the name of the man.
He has been campaigning on social media, with the hashtag #FindMike.
His story has spread over Twitter, with many people showing support for suicide awareness.
If you have any information you can contact firstname.lastname@example.org.
For confidential support in the UK call the Samaritans on 08457 90 90 90 or visit a local Samaritans branch.