But he insists he is not fussed about success – because he sees his songs as a form of therapy for himself.

His years of hard work were rewarded this year when singles The A-Team and You Need Me, I Don't Need You both made the top five, while his album, simply entitled +, went straight to the top of the charts.

Yet the 20-year-old, who plays the O2 ABC in Glasgow tomorrow, is a modest sort.

"I don't really write songs to have success with them," he says.

"I write songs to have therapy and to get stuff off my chest. If the songs end up a success then great, but I never really write thinking, 'Oh, this could be a Top 10 hit' or 'This one will go down well at festivals'. I just write because I need to."

He started to write while in his teens, releasing his first independent EP in 2005, and then going on to release two albums before moving to London.

His relentless gigging earned him support slots with Just Jack and Example.

But Ed, from Halifax, Yorkshire, admits the long journey took its toll on him.

"I lost faith in April last year and decided to go to America for a bit," he says.

"While there I became enthusiastic again and when I came back I got into the full swing of things again."

That new-found inspiration came partly from an unlikely source, in the shape of American actor and singer Jamie Foxx. The star of films such as Collateral and Ray heard Ed sing at an open mic night and invited him to stay at his house and record material for the rest of his stay.

"I never expected that," says Ed. "While I was there, there were so many other crazy things happening it felt normal. Then, when I got home, that's when it hit me. I thought, 'Wow, that was pretty cool'."

Now, he is ready for his biggest UK tour to date.

"It's going to be an interesting step up on this tour," he says.

"I have played these sort of venues only as a support act, to Just Jack and Example, so I am looking forward to headlining them myself.

"I am not using a band and am going to keep doing it solo, so it will have its own intimacy."

He might, however, be joined for a duet by his support act on the tour, Edinburgh singer Nina Nesbitt. It is a link-up that came about in unusual circumstances.

The singer explains: "I did a gig a radio gig above a pub in Edinburgh the other week, and this girl came with her mum.

"Her mum said, 'Let her sing', and I told her I needed to get on with my songs.

"But the host took a while to turn up, so I gave Nina a guitar and let her play some songs. She was really good, so she will be opening the ABC show."

Ed's parents are surely delighted at their son's success – especially as they had to spend years listening to him practise.

"When I first picked up a guitar, I just played it every hour of the day. then I was singing every hour of the day," he says.

"One way to get out of irritating people all the time by singing and playing all the time was to make it my job, and then that could be my excuse.

"I did irritate people when I was younger. I used to keep my parents up late at night with my singing!"

l Tomorrow's concert at the O2 ABC, Sauchiehall Street, is sold out.