Following behind the Queen (5)
I believe the answer is:
after
'following' is the definition.
(I've seen this before)
'behind the queen' is the wordplay.
'behind' becomes 'aft' (aft means towards or at the end of a ship).
'the queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'aft'+'er'='AFTER'
(Other definitions for after that I've seen before include "Coming later in time" , "In honour of" , "Looking for" , "Chasing" , "Following - behind" .)