Make A Pig's Ear Of Meaning

(Britain, idiomatic, transitive) To do badly; to make a mess of.

Example: 2013, Daniel Taylor, Rickie Lambert's debut goal gives England victory over Scotland (in The Guardian, 14 August 2013)[1]
  England responded with goals of their own from Theo Walcott and Danny Welbeck and, on the balance of play, deserved the victory. Yet there were long spells when they threatened to make a pig's ear of it.
2003, Kate Walker, Desert Affair, ISBN 9780373122974, p. 140:
  Instead, he had lain awake for hours, knowing he'd made a pig's ear of everything, and trying to think of a way to sort things out.