For reasons not to be suspicious of barristers and judges, see Saxmere Co Ltd v Wool Board Disestablishment Co Ltd  NZSC 72 (3 July 2009).
The case is about how to decide when apparent judicial bias exists. Although a civil case, it is relevant to criminal law and the accused's right to a fair trial.
It is a reminder of what the independent bar is all about. Barristers are independent of their clients, as well as from anything that could deter them from their task of ensuring that the judicial process is correct in law.
Judges share that objective, so bench and bar are engaged in the same task. This means that judges couldn't care less which barrister wins or loses, and barristers couldn't care less (surprising though this may seem) whether their clients win or lose. It is the process that matters.
Inevitably, there will be times when judges know barristers in cases before them quite well. They may even share business interests. That is completely irrelevant in the courtroom. But does it look OK?
The impression gained by the fair minded observer is the touchstone. She (for she is apparently woman: Helow v Secretary of State for the Home Department  UKHL 62, noted here 23 October 2008) will be aware of these characteristics of the judicial process: Saxmere para 6 per Blanchard J. These are the points made in Aussie Airlines Pty Ltd v Australian Airlines Pty Ltd (1996) 135 ALR 753, 767 (Fed CA), quoted by Blanchard J at para 7 of Saxmere.
She will be aware of the judicial oath and the obligation of judges to hear the case that has been allocated to them and not to pick and choose which case they will hear. She will remember that the party seeking to overturn a decision for reasons of apparent bias may well be the least objective observer of all. At the same time, she will realise that judicial protestations of absence of influence are not decisive, as unconscious bias may have operated. Before she perceives apparent judicial bias, she will need to identify what it is that might lead a judge to decide a case on other than its legal and factual merits, and she must be able to point to a logical connection between that thing and the feared deviation from deciding the case on its merits: Ebner v Official Trustee in Bankruptcy (2000) 205 CLR 337 at para 8.
[Update: this judgment has been recalled and the orders made in it set aside, and the case was remitted to the Court of Appeal for rehearing:  NZSC 122 (27 November 2009). This was because the Supreme Court had not been made aware of all the matters relevant to apparent bias, and if the Court had known of them it would have concluded that apparent bias was established.]