Hollow surprise, with new head of squad at end of Prime Suspect (5)
I believe the answer is:
sense
'suspect' is the definition.
(sense can mean to suspect or have a feeling)
'hollow surprise with new head of squad at end of prime' is the wordplay.
'hollow' suggests removing the centre.
'with' is a charade indicator (letters next to each other).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'head of' indicates taking the first letters.
'at end of' indicates one should take the final letters.
'surprise' with its middle removed is 'se'.
The initial letter of 'squad' is 's'.
The last letter of 'prime' is 'e'.
'se'+'n'+'s'+'e'='SENSE'
(Other definitions for sense that I've seen before include "Become aware of" , "One of five main faculties" , "Suspect" , "eg Vision, hearing" , "Faculty of perception" .)