Of course you're right about who's really in control.
However...
The bureaucrat's natural instinct is the path of least resistance leading to no comebacks.
So if one of his political 'masters' requests, for example, a safety 'improvement' which costs the bureaucrat little or nothing and can attach no blame to him later - well, of course he'll indulge the MP and give him a nice ego-boost and a few cheap votes. Someone always ends up paying and it's always Us, one way or another, never Them.