Whilst UAV's can perform certain tasks such as stand off reconnaisance. I still fail to see that a UAV can perform all the missions that a Nimrod can.
There have been certain missions where a Nimrod was asked to do unconventional things, and these break's from the norm resulted in successful conclusions. A large noisy jet aircraft is much more imposing than a UAV, as a UAV is no more threatening than a remote control aeroplane.
To answer the argument over the E3D, When I first arrived at Ice Station Kilo, as a wide eyed LAC many moons ago, a Nimrod was practicing a flying display. Those of you who know how manouverable a Nimrod is will understand when I say that I have never seen an E3D move around like that! Those in the know, please correct me if I'm wrong but is not manouverability an important factor? Just an after thought, but I can't see an E3D flying at 200ft over the ocean either.
I still stand by my original statement. The Nimrod's role is so misunderstood, that people just don't understand what it does, hence, they don't see the point of it. A comment like the russians ageing fleet is holed up in port, and ageing diesels are being sold off to insignificant countries only proves this.
Alas, I also can see a future where we have MR2's with an upgraded mission suite. However, this must still be better than when the MR1's came in - nice new shiny airframe with an old Shackleton suite.