Audi alteram partem in the context of "Trial in absentia"

In English law, natural justice is technical terminology for the rule against bias (nemo iudex in causa sua) and the right to a fair hearing (audi alteram partem). While the term natural justice is often retained as a general concept, it has largely been replaced and extended by the general "duty to act fairly".

The basis for the rule against bias is the need to maintain public confidence in the legal system. Bias can take the form of actual bias, imputed bias, or apparent bias. Actual bias is very difficult to prove in practice whereas imputed bias, once shown, will result in a decision being void without the need for any investigation into the likelihood or suspicion of bias. Cases from different jurisdictions currently apply two tests for apparent bias: the "reasonable suspicion of bias" test and the "real likelihood of bias" test. One view that has been taken is that the differences between these two tests are largely semantic and that they operate similarly.