Queen is surrounded by ticket sellers and trippers (8)
I believe the answer is:
tourists
'trippers' is the definition.
(people on trips)
'queen is surrounded by ticket sellers' is the wordplay.
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'surrounded by' is an insertion indicator.
'ticket sellers' becomes 'touts' (as in ticket touts).
'r'+'is'='ris'
'ris' put within 'touts' is 'TOURISTS'.
'and' acts as a link.
(Other definitions for tourists that I've seen before include "Group of visitors" , "Visitors and sightseers" , "They travel for pleasure" , "Holiday-makers from abroad" .)