Ahhh Leon, you poor soul - you have fallen for the old "don't worry, the DD's, FF's and helos can cover the gap left by Nimrod" line!
As has been said, fine if one of the few ships we have left just happen to be where they are needed when they are needed, but even in the past they were usually late to the party, arriving long after the Nimrod had been 'busy' for many hours, if not days!
For some ops this may well be acceptable, for others less so. For SAR this is definitely NOT acceptable, and neither is sending a VC10 out over the Atlantic to do SAR, as has happened relatively recently!