Means of communication some parliamentarians sent up (1-4)
I believe the answer is:
'means of communication' is the definition.
(I've seen this before)
'some parliamentarians sent up' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'sent up' is a reversal indicator.
'liame' can be found hidden inside 'parliamentarians'.
'liame' reversed gives 'E-MAIL'.
(Other definitions for e-mail that I've seen before include "A lime (anag.)" , "Electronic letter" , "Online correspondence" , "Fast communication" , "Online post" .)