Trade Bill

I am trying to understand the noble Lord. Obviously, the definition of a customs union is quite difficult and I was trying to follow his definition. Does he intend only the narrow definition of a customs union, where it essentially just deals with issues such as tariffs and excise duties, or does he intend it to include the regulatory alignment, as it often does because the terminology gets stretched? If there is not regulatory alignment there still have to be checks, which means we are back to the border problem. Would he explain what he sees as the content of “a customs union” because, if we are not removing the border problem, I struggle to understand his point?