Okay, being a police pilot here in the US is a little bit different. And I understand the differences between here and the UK, and really do not want to get into the 'ole discussion of police pilots and civie pilots, but observers is a different thing.
When I was a ground pounder and the helicopter was above me, I knew that the observer knew what was happening and potentially going to happen. I knew that he/she had been there and had the same line of thought I was having. What I might do or what the bad guy might do. Very important as I can't always give a full dissertation while I was running/fighting the guy. I knew that from his experience that he would be coordinating a response that best fit the situation.
There has been a lot of discussion on the pilots being ex military and having so much more experience then a regular civilian in-order to do the job safely, is that not the same for an observer (being a police officer over some one that is trained by rote)?
Sorry zorab64 did wind me up a little.