Just another thought whilst I was bimbling down the shops.
I am currently working on a training establishment and am at logger heads with my peers over one particular lesson. The lesson is about SAR, where the Nimrod is listed alongside VC10's, Tristars and E3D's as an aircraft that can assist in SAR activities. This view combined with the fact that much of what Nimrod does can not be talked about, explains why certain people think that if we need it, we only need a few.
The Nimrod's role is very, very diverse and is not limited to hunting submarines and ships or indeed SAR. It has arguably, always been (and will be, when BAe get their act together) the ONLY true multi-role aircraft the RAF has!
Do we need a new airframe? - YES!
Should it be a Nimrod? - YES!
Is three enough? - NO!
Do we need as many as possible? - Absolutely YES!