"The decision to make today's arrest was taken solely by the MPS without any ministerial knowledge or approval" - so says the Metroplitan Police Service
But the Met told the Speaker that they were about to arrest Damian Green, and they told the Mayor of London, and they told the Leader of the Opposition. If they told all of them, why on earth wouldn't they tell ministers as well?
Assuming as we must that the Met briefing is accurate, the only possible answer is that Home Office ministers are incompetent, disregarded and irrelevent. However you cut it: "not fit for purpose."