It has been said that “it is not merely of some importance but it is of fundamental importance that justice should not only be done, but should manifestly and undoubtedly be seen to be done.” 
In this way, the driver of this test is the strong public interest in ensuring public confidence in the administration of justice.

Remember that we are trying to prove APPARENT bias and not actual bias because of the sheer difficulty of proving actual bias given its insidious nature!

Hence, we are to take into account these characteristics of the reasonable person when applying the test to the facts. 

However, he/she is said to be a "layman" and does not have in-depth legal knowledge of court proceedings, special expertise, or other matters outside the ken of the reasonably well informed member of the public.

Hence, we are to take into account these characteristics of the reasonable person and apply them to the facts. 

The claimants commenced proceedings against the defendants for trespass in respect of a wall built on land to which the claimants claimed they had title. A trial took place in the county court. The judge informed the parties that the claimants' solicitors had drafted his will, which they continued to hold, but no one objected to him continuing to hear the trial. Judgment was given against the defendants and they appealed on the ground, inter alia, that there was an appearance of bias because of the judge's relationship with the claimants' solicitors. It was then disclosed to the defendants that the judge and his wife had used the services of the claimants' solicitors to amend their wills the night before judgment was given. The appeal was dismissed. Subsequently, the defendants learnt that the judge did not pay for the services provided by the solicitors during the trial and they sought permission to reopen the appeal.