the response to the vetting given to the government would have been a simple pass or fail
these things dig deep and the details are surely kept confidential
I know that. I've been involved in DV, and I guess you have too. Trying to explain the principles to others to aid understanding.
I would imagine the first line response would be from the vetting team to HR "based upon the developed vetting exercise, we recommend against appointment".
FCDO HR then inform FCDO of this position.
It appears (and I look forward to both Starmers statement and the select committee next week) the FCDO then chose to appoint anyway.
In this process, the PM would understand the process to be that DV has been passed.
It is possible FCDO went to someone in no 10 (outside of the cabinet office - probably a SPAD like McSweeny) and said the decision is non appointment.
To which the response is "why?".
"DV wasn't passed".
"Ok, thanks. We should look to appoint anyway. The risks, whatever they are, can be mitigated"
Mandelson was always an appointment on the basis of what he could do, and avoid, would outweigh his bad sides.
Politically, if Starmer did know the DV recommendation was to not appoint, then he has to go. I highly doubt he knew; however I am sure the risk appetite described above would have been part of earlier conversations.
We live in horribly murky times - staying squeaky clean in this environment is almost impossible.