The man, who we have dubbed 'John', decided to give away his £150million after realising he would never get around to spending it.
Nick Fisher, from Stockport, first met the mystery millionaire in March last year at a pay and display car park in Oxford.
John approached Nick and asked him for £1. Seeing the man had a £150,000 Bentley, Nick started laughing, assuming it was a joke then John explained he had left his wallet at home. Nick gave the man the pound but as he turned to walk away. The mystery millionaire handed Nick £100 in two £50 notes and gave back the £1.
Nick said he was ‘lost for words’ and said: “It was just for being kind and helping him.”
“I actually started laughing and asked him was he taking the mickey. I also thought it was being filmed for one of those prank type TV programmes where members of the public are set up and I looked around for hidden cameras.”
John gives out the money by putting them in pockets of clothes in shops, inside newspapers as fake parking tickets.
He has also gone through the alphabet, picking a town or city from each letter and sending five houses £200 in a Christmas card.
For two years running, Chichester has been picked as one of the locations.
"Unbelievable, I know, but it's true", said Nick.
After their first meeting, Nick spotted John's number plate — two letters and two numbers — and passed the details to a friend who could track his address. After getting the information, Nick sent John a copy of a book he had written, and a letter of thanks.
He said: "I included a note with it saying that I hoped he appreciated the humour like I appreciated the £100 he gave me. He then contacted me and we exchanged emails, in one of which I asked him if he'd ever thought about writing a book about what he does, which is how the book materialised."
For more information on the book visit the website here.