Disgraced soldier Ben Roberts-Smith will be forced to pay nearly all of Nine Entertainment’s costs in a high-profile defamation case because he knew before launching legal action that he was a war criminal.

Justice Anthony Besanko ruled on Tuesday that Mr Roberts-Smith should pay the media company’s costs on an indemnity basis – meaning he would need to pay roughly 95 per cent of Nine’s costs – from the start of the proceedings in 2018.