Secured position moving badger hide (10)
I believe the answer is:
bridgehead
'secured position' is the definition.
'moving badger hide' is the wordplay.
'moving' indicates an anagram.
'badger'+'hide'='badgerhide'
'badgerhide' is an anagram of 'BRIDGEHEAD'.
(Other definitions for bridgehead that I've seen before include "Strong position secured inside enemy territory" , "Secured position from which to advance" , "Advantageous position" , "defensive position" , "Advanced position secured in enemy territory" .)