The UK rights for the Apprentice belong to the BBC and not Sugar, so he couldn't do that.
Well, he has publicly threatened to do that, and apparently his contract is non-exclusive:
I sincerely doubt that he'd make that threat if he wasn't able to do it. He's a hugely successful individual, he didn't get where he is making empty threats. He strikes me as being very honest and straight-talking, and all of the past candidates have said as much. If he says he is able to take it to another channel, then he is. Whether or not he will remains to be seen.
Unless of course, he has been hideously misquoted in the article, which is a possibility.