His have songs have sold millions across the globe.

But few in his home country may have heard of the Scot behind the song that could win this year's Eurovision Song Contest.

John Ballard, 64, who grew up in Drumchapel, Glasgow, is part of the songwriting team behind Sergey Lazarev's You're The Only One, Russia's entry to the annual song contest and among the favourites to win the contest.

Ballard, who has lived in Sweden since the 1970s has already experienced considerable success in pop music, as one of the primary song writers and producers of the Swedish pop band Ace of Base, who sold 30m albums worldwide.

In 2013 his song for the entry in the Eurovision song contest for Azerbaijan, Farid Mammadov's Hold Me, came second, and a song he wrote for Russia in 2014 came seventh.

You Are the Only One - the chorus of which was inspired by an old song by the late Scottish folk singer Hamish Imlach, The Zoological Gardens - would mark the first winning entry for the Glaswegian, who runs an eight studio complex in Gothenburg.

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As a young man Ballard performed on the folk scene in Scotland and the UK, playing with performers such as Billy Connolly and Matt McGinn before relocating to Sweden.

"I know it's never really been a big thing in the UK, but the Eurovision is massive in Europe," he said.

"It is like the World Cup of football, and I am thrilled to be in it again.

"We came close with Azerbaijan, we got the most votes worth [the maximum] 12 points in the competition but came short - to be honest, politics always plays a part in the voting process, as I am sure people know.

"I think this year it is a great Eurovision song, and we have a chance."

The Herald: Ballard - a fan of Rangers FC who has written a song for the club's supporters, Still A Blue - said the Imlach song was a source of inspiration for a song which will soon be heard on televisions across the continent.

The semi-finals of the contest will take place in Stockholm on 10 and 12 May, with the final on 14 May.

"I was thinking of Hamish's song, which mentions thunder and lightning, and I thought: not many people use that phrase in songs," he said.

"I looked it up, and it is not a common phrase, and I thought it could be explosive - but the first time I heard it was Hamish."

Ballard first discovered Ace of Base when they were called Tech-Noir, and worked with the band - Ulf Ekberg, Jonas Berggren, Malin Berggren and Jenny Berggren - on three albums, writing and producing songs.

Now more than 200 gold, platinum and diamond records adorn the walls of his Tuff Studios complex in Gothenburg.

Ballard said he would love to be involved in a future UK or Irish entry to the competition, a contest which is often regarded not entirely seriously in the this country.

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"I would love to be involved in a UK entry, but to be honest I don't know where to start, and I would be interested in working with Ireland too," he said.

"I am proud of the work I have done but I am still a Scotsman and I still feel very strongly about the old home country.

"I would love get a chance to do it if I could."

Another Scot, Bill Martin, penned a song which won the Eurovision for the UK in 1967, Puppet on a String, sung by Sandie Shaw.

Lazarev has said the song he sings is of "incredible magnetism and power."

He added: "When I heard it for the first time in the studio, I was amazed by its emotional glow, energy and significance. This song influenced my decision to accept the offer to participate in the Eurovision Song Contest".