Aerial used by social worker before queen turns up (7)
I believe the answer is:
antenna
'aerial' is the definition.
(I know that aerial can be written as antenna)
'social worker before queen turns up' is the wordplay.
'social worker' becomes 'ant' (ants are social insects).
'before' means one lot of letters go next to another.
'queen' becomes 'anne' (Queen Anne, 18th-century queen).
'turns up' shows that the letters should be reversed in order.
'anne' back-to-front is 'enna'.
'ant'+'enna'='ANTENNA'
'used by' acts as a link.
(Other definitions for antenna that I've seen before include "Transmitting aerial" , "Insect's feeler" , "receiver" , "connected to 41?" , "Feature of dish" .)