London is the biggest city in the UK so therefor it must have the biggest police service.
That is NOT what you said previously and not what I questioned. You said, and I quote:
... get to the position of assistant commissioner of the most important police force in the UK.
'Biggest' and
'Most Important', there is a big difference in those two statements. I did not question The Met being the biggest Police Force in the UK. I did/do question which, if ANY Police Force in the UK is the
'most important'.