When you are an expert in a civil court case, you must follow the court's rules for preparing and giving evidence. You have to do what the rules say when you are getting ready to give your expert opinion and when you are actually giving it. If you do not follow the rules, the Judge might not let you give your evidence unless they say it is okay.

If you want to give expert evidence but you did not follow the rules, you need to ask the Judge for permission first. The Judge will decide whether or not to let you give your evidence. You should know what the rules are so you can follow them and give your evidence without any problems.