Mandelson was a political appointment. The FCO would never in a geological age have appointed a self serving creep like him to the top job. It would have been a diplomat who has risen to the top through decades of hard work and merit.
Mandelson knows where the political bodies are buried not the civil service bodies.
That a civil servant who was not even in situ when the appointment was made has been forced to fall on his sword to protect his political masters who caused the issue is a disgrace.
Starmer should go save, as others say, he will be replaced by someone considerably worse at a time when even bland low grade continuity is preferable.