Civil Service welcoming a politician, upper-class, in study area (6)
I believe the answer is:
campus
'in study area' is the definition.
(I've seen this before)
'civil service welcoming a politician upper-class' is the wordplay.
'civil service' becomes 'cs'.
'welcoming' is an insertion indicator (in sense of 'inviting in').
'politician' becomes 'mp'.
'upper-class' becomes 'u' ('u' can be similar in meaning to 'upper-class').
'a'+'mp'+'u'='ampu'
'cs' placed around 'ampu' is 'CAMPUS'.
(Other definitions for campus that I've seen before include "university territory" , "Area around a university" , "University estate" , "university environment" , "University grounds, etc" .)