If you are talking about Nel, well just this very moment, Sky's reporter AND the advisory lawyer of the day have just said exactly the same as I, that Nel has called OP a "liar" several times a day so far, so why the admonishment now is very strange.
If you are talking about a case I was litigation friend to, I can't remember, but you're probably right and our barrister said to the witness he was lying. It concerned what was alleged to be a 5 year-old photocopy of a lost original. New evidence miraculously turning up and being disclosed with the court's permission on the last day of the trial, but on which you could feel and see at the back the indentation caused by a black biro used to add the hand written notes. Our barrister's summing up words for that witness who was duped by his spouse to present the document to support her in a breach of trust case against her concerning vulnerable adults were, "... he entered the box a dishonest man, but left it an honest one". Not surprisingly the witness left his spouse very soon after she was found guilty of fraud against the adults.