Developing army corps set up information outlet at last (8)
I believe the answer is:
emergent
'developing' is the definition.
(I've seen this before)
'army corps set up information outlet at last' is the wordplay.
'army corps' becomes 'reme' (Royal Electrical and Mechanical Engineers).
'set up' is a reversal indicator.
'information' becomes 'gen' (gen can informally mean information).
'at last' indicates one should take the final letters.
The final letter of 'outlet' is 't'.
'reme' back-to-front is 'emer'.
'emer'+'gen'+'t'='EMERGENT'
(Other definitions for emergent that I've seen before include "achieving prominence" , "Rising" , "Suddenly appearing" , "Coming into existence" , "Newly independent" .)