X Factor judge, Louis Walsh, has admitted that he believes Nadine Coyle is the best singer in the group.

Speaking to The Guardian this weekend, their former manager said: 'There was a girl in Ireland called Nadine Coyle, and I said, go for this show. She is an amazing vocalist. A real, real singer. So I pushed her in the band, and I said Nadine is the lead singer."

'From then on, there were problems. "I never worked with them very well 'cos they kind of scared me, the five girls together. Five girls! Five girls is a bit scary.

"They were all a bit scary. Generally, girls don't like each other. That's the problem. I couldn't help them with their hair, makeup, all those things. And from the moment I said Nadine was the best singer, the others alienated me.

"Well, she is the best singer! By a mile. But she didn't marry a footballer. If she'd married a footballer she'd have been a big star."

When Cheryl Cole joined the X Factor panel of judges, the tension continued. Walsh said:

"Cheryl knows how to work it. Cheryl is all about Cheryl."

Watch the video for Nadine Coyle's 'Insatiable' below: