For the best part of four years, Derek Harris’ soft trills and gentle words have stopped many passers-by in their tracks on Hampstead Heath.

From his favourite bench outside Kenwood House, the self-taught guitarist has brought tears to the eye, moved ramblers to sing and now he has inspired a YouTube video which has gained more than 800 hits.

At 64, dressed in a raggedy brown parka, rarely clean shaven and often ill because he insists on playing in the park come rain or shine, the troubadour is an unassuming internet hit.

He admits his act is not about perfection. “I’m not saying that I’m amazing or good,” he said. “It’s just that music is powerful and I want to use it to inspire people who have a dream to just go out and do it.”

When his mother was diagnosed with throat cancer a few years ago, Mr Harris gave up work to care for her. Her death hit him hard.

“I started playing to get over the grief; it was sort of a healing process, but you never forget something like that.

‘‘It’s always in my subconscious.Everyone loses parents and everyone experiences sadness. I think that’s why my music speaks to people.”

Last month, he was spotted on the Heath by a young couple who work in the music business.

“They asked me if I had a CD,” said Mr Harris, from Finchley.

“I said I didn’t, I had never thought about something like that.

“And then they said, ‘Would you like to be in a film?’ I was surprised, I had only just woken up and I had a rotten cold.”

Mr Harris said he was stunned to learn that the on-the-spot recording of his song Don’t Look Back gained any YouTube following at all.

“The thing that really got me is that I’m not a young person, I’m in my 60s and it amazed me that people were drawn to it.”

For Mr Harris, it’s not about getting a record deal or selling out gigs, he hopes his tender melodies touch as many people as possible.

“I hope that I inspire people to do whatever it is that makes them happy.”

n Mr Harris can be seen outside Kenwood House most days. His YouTube video is at www.youtube.com/watch?v=simKiebdkkg