Scotland Bill

My Lords, I am very puzzled by this. The Minister says that the amendment is competent. The Minister says that it was included in Calman. The Minister says that the Bill is about implementing the Calman proposals. The levy is certainly subject to a legal challenge. He did not explain why the fact that it is subject to a legal challenge precludes accepting my amendment and putting it in the Bill, and making that a devolved tax for the Scottish Parliament.