How does the USPTO handle United Kingdom provisional specifications in priority claims?

The USPTO handles United Kingdom provisional specifications in priority claims as follows:

• A certified copy of the “provisional specification” may be submitted, sometimes accompanied by a copy of the “complete specification.”
• The provisional specification is examined for completeness of disclosure, as it may not contain a complete disclosure in the sense of 35 U.S.C. 112.
• If the UK provisional specification is found insufficient for lack of disclosure, reliance may then be placed on the complete specification and its date, treating it as a different application than the provisional specification.

The MPEP states: “In applications filed from the United Kingdom there may be submitted a certified copy of the ‘provisional specification,’ which may also in some cases be accompanied by a copy of the ‘complete specification.’ According to United Kingdom law the provisional specification need not contain a complete disclosure of the invention in the sense of 35 U.S.C. 112, but need only describe the general nature of the invention, and neither claims nor drawings are required.” (MPEP 216)