Rumours suggested Cowell and other executives at the company had dropped the U.K. X Factor winner after he wrote a song about terrorism, and now it seems the stories are true.
Arthur took to Twitter.com late on Tuesday to confirm he had moved on, writing, "Just to clear things up - I am no longer with Syco. I would like to thank all at the label for making a great record with me.
"I now have to move on and do something different - the future is bright!"
Arthur sparked controversy with the lyrics to his song Follow the Leader, in which he sang "I'm gonna blow up your family like I'm a terrorist", and then attempted to play down the fuss, insisting he was "not promoting terrorism".
Arthur has become the latest X Factor winner to depart Cowell's label - Matt Cardle, Joe MCElderry and Steve Brookstein were all dropped and last week (ends06Jun14), Leona Lewis announced she had left the company after seven years, signing a new deal with Island Records.