Boris Sprinkler
Dont be scared
No.Yes, as you can see it's totally un-manned, so anyone could just slip inside the airport perimeter, hi-vis jacket and you're all set.
Even 20 years ago they had cameras around all perimeter roads that could zoom in on your face from some distance to clearly identify you to a control room staffed 24/7 by staff from various agences. Because it is critical national infrastructure and the British do paranoia quite well.
You weren't slipping through by accident on purpose.
Not to mention all the plane spotters who hung about in the area too.