Despite his success Leon, from Whitburn, West Lothian, still plans to have a quiet Christmas and New Year. 

He said: “I don’t know what this year will be like. I’ll just sit in with my mum and watch the bells on the TV eating steak pie and peas.”

TV insiders say it was Leon’s modest background and down-to-earth demeanour that endeared him to audiences. He regularly told the judges: “I’m just a young lad from a wee town in Scotland.”

He has experienced a meteoric rise to fame, having left his job as a sales assistant with Gap in Livingston for The X Factor series.

A former Whitburn Academy pupil, Leon had only sung in his bedroom before a pub karaoke singing competition in January set him on his road to stardom.

After having been coerced to go by friends, with his first performance – an attempt at fellow Scot Paolo Nutini’s song Last Request – he became a favourite with the crowd, and went on to win the £50 prize three times in three months.

But it was only when he recorded himself on his iPod that his family believed he could go on to become a star. Bowled over by his hidden talents, his mother, Wendy, encouraged him to go along to The X Factor auditions in Glasgow.

However, in one of his first performances, waspish judge Simon Cowell described his version of The Beatles’ hit Can’t Buy Me Love as a “complete and utter nightmare” and said he did not warrant a place in the series.

But as the weeks progressed, he slowly gained confidence, particularly with praise from stars such as Celine Dion, Girls Aloud, and his idol Michael Bublé.

Leon, who has a black belt in karate, grew up without his father, Phillip, who walked out when he was only two and tragically died a short time later. He regularly told viewers how he wanted to win The X Factor to repay his mother for bringing him up.

The receptionist at a GP’s practice in Bathgate has been leading the campaign to turn her son into a star. Windows of cars and houses and offices were plastered with his picture and “Vote Leon!” emblazoned underneath.

Mrs Jackson, 40, said last night: “He was never into singing or performing at all and he wasn’t musically minded. 

“He liked his sports and activities more.

“This journey will now change our lives. He’s gone from singing karaoke back in January to this.” 

Leon’s debut single When You Believe was put into production immediately after last night’s show and will be on sale in shops from Wednesday.