Respectable regiment is escorted outside and dispersed (13)
I believe the answer is:
decentralised
'dispersed' is the definition.
(both can mean scattered or distributed)
'respectable regiment is escorted outside' is the wordplay.
'respectable' becomes 'decent' (similar in meaning).
'regiment' becomes 'RA' (Royal Artillery).
'escorted' becomes 'led' (to lead someone somewhere is to escort them).
'outside' means one lot of letters goes inside another.
'is' put within 'led' is 'lised'.
'decent'+'ra'+'lised'='DECENTRALISED'
'and' is the link.
(Another definition for decentralised that I've seen is " Put out to local government".)