Half of children in revolting party (4)
I believe the answer is:
ukip
'half of children in revolting party' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'half of children in revolting party' is the wordplay.
'half of' suggests halving the letters.
'children' becomes 'kins' (I've seen this in another clue).
'in' means one lot of letters goes inside another.
'revolting party' becomes 'up' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'kins' with half the letters taken is 'ki'.
'ki' inserted inside 'up' is 'UKIP'.
Can you help me to learn more?
(Another definition for ukip that I've seen is " Far-right Eurosceptic British political party, founded 1993".)