It is a basic principle of English law that a judge should not sit to hear a case in which “the fair-minded and informed observer, having considered the facts, would conclude that there was a real possibility that [s/he] was biased”. It is an even more fundamental principle that a judge should not try a case if he is actually biased against one of the parties. The concept of bias includes any personal interest in the case or friendship with the participants, but extends further to any real possibility that a judge would approach a case with a closed mind or, indeed, with anything other than an objective view; a real possibility in other words that he might in some way have “pre-judged” the case.
If you feel that a particular judge in your case is biased against you (for example if they say right at the beginning of a hearing that they are going to insist on a father having contact or they don’t believe a word you’re saying) you can ask the judge to recuse themselves or step down simply by saying verbally or in writing something like:
“I hereby make an application for you to recuse yourself on grounds of your bias or apparent bias”.
When you (or your lawyer) says this, the judge is supposed to immediately stop the proceedings and pass the matter to a more senior colleague to continue the proceedings. If the judge refuses to do this or just dismisses what you say without responding, you are entitled to appeal and the proceedings must stop until that appeal has been dealt with. To make an appeal you need to make an Application to court under the Civil Procedure Rules (in this case CPR 23). (For more on case law see Family Law Week, 2017)