Full power to break up telecom organisation (8)
I believe the answer is:
complete
'full' is the definition.
(associated in meaning)
'power to break up telecom organisation' is the wordplay.
'power' becomes 'p' (symbol in physics).
'to break up' is an insertion indicator (inserted letters break up or split the word).
'organisation' indicates anagramming the letters.
'telecom' with letters rearranged gives 'comlete'.
'p' going into 'comlete' is 'COMPLETE'.
(Other definitions for complete that I've seen before include "Whole and unabridged" , "Having all the necessary parts" , "accomplished" , "Execute" , "whole,entire,uncut" .)