Retain power with body of troops available in emergency (8)
I believe the answer is:
preserve
'retain' is the definition.
(thesaurus)
'power with body of troops available in emergency' is the wordplay.
I cannot really see how this works, but
'power' could be 'p' and 'p' is found in the answer.
'troops' could be 're' (Royal Engineers army regiment) and 're' is found within the answer.
The remaining letters 'serve' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for preserve that I've seen before include "Keep from decay, corpse or food" , "Keep out of harm's way" , "Keep safe from spoilage" , "Jam; safeguard" , "Toast option" .)