If The Judge Feels He Has Misdirected The Jury On A Point Of Law.

https://news.sky.com/story/chelsea-footballer-sam-kerr-not-guilty-of-racial-harassment-over-stupid-and-white-remarks-13306785

Then it is the Judge's duty to declare a mistrial.

No matter how embarrassing for him that must be, personally.

Although I assume the S.2 Crim Dam (1971) matter is yet to be heard.

Even at the low end of sentencing,  that's either Australia or America's welfare bill to pick up now.