Tip waste food over press and sackings are on the cards! (5,4,4)
I believe the answer is:
heads will roll
'sackings are on the cards' is the definition.
(phrase meaning some people will be punished)
'tip waste food over press' is the wordplay.
'tip' becomes 'head' (head is a kind of tip).
'waste food' becomes 'swill' (food waste fed to pigs).
'over' says to put letters next to each other.
'press' becomes 'roll' (to press down with a roller).
'head'+'swill'+'roll'='HEADS WILL ROLL'
'and' is the link.
(Other definitions for heads will roll that I've seen before include "People are going to cop it" , "Someone will have to pay for this!" , "People are going to pay for this!" , ""Some of you will be fired for this!"" , "People are going to carry the can" .)