Was Keir Starmer really kept in the dark over Mandelson's failed security vetting?

It is beyond all credibility that the prime minister was not informed that Lord Mandelson had failed his security vetting prior to his appointment as ambassador to the United States. Keir Starmer says he wasn't told until Tuesday this week. It is both incredible and unbelievable. This is simply not the way Whitehall works. Number Ten is involved in everything to do with national security and intelligence. Either there has been a conspiracy against tfhe prime minister at the heart of the Foreign Office which supposedly kept Starmer in the dark about Mandelson's vetting failure or the leader of the government was so busy with world affairs issues that he failed to read or comprehend the document that lay before him on his desk in Number Ten that revealed the pieve of devastating news: that his chosen individual for the ambassador's job in Washington was considered a national security risk and, thus, shouldn't be appointed. There HAS to be a document spelling this out, and, incidentally, there would have been copies circulated, for example, to the Chief of the Secret Intelligence Service and to the director-general of MI5. and the head of the Foreign Office's Senior Appointments Committee etc etc. This document will be sitting in a lot of filing cabinets throughout Whitehall. PLEASE BUY AGENT REDRUTH, MY NEW SYP THRILLER PAPERBACK. AMAZON, ROWANVALE BOOKS, WATERSTONES.