Simon Cowell has banned Niall Horan from The X Factor

Simon Cowell is not a man to be messed with.

The music mogul is known for not holding back when it comes to giving his opinions, giving harsh criticisms to people everywhere. When we heard Niall Horan was embarking on a solo career, we were thrilled for the This Town singer however it seemed to strike a chord with Simon. Speaking about Niall's debut single, Simon said

"He probably would have had a No 1 single if he’d stayed with me. "But you know who does have a No 1 this week? James Arthur. Very pleased he’s back with us with a  fantastic record... Hashtag loyalty."

As if those remarks weren't catty enough, it seems Niall signing up with Universal instead of Simon's SyCo label has really miffed Simon off further - as he has banned the Irishman from performing on the live shows in the future. According to The Sun on Sunday, a source has said Simon banned Niall from the show entirely.

"Simon really thought the 1D boys would show loyalty after he mentored them on the show and made them the huge global success they are. Instead they went behind his back. "He's not going to be doing them any favours. He knows artists love performing on the show as there are eight million viewers to promote their songs to."

Also, the fact that Niall was already singing on The Graham Norton Show has miffed Simon off, as the X Factor judge "doesn't want acts who have been elsewhere". Yikes Simo!