The truth, the whole truth and nothing but the truth in Australian affidavits

The promise to tell “the truth, the whole truth and nothing but the truth” is familiar to most people who have seen a court proceeding either on television or in real life. The phrase is used as part of the oath administered to witnesses who are giving oral evidence in court in Australia.

The wording requires the witness not just to tell the truth, but also that it be the “whole truth.” This is slightly different from the wording often used when a witness swears or affirms an affidavit in Australia, which sometimes does not include a reference to the whole truth. There is therefore a question about whether the person swearing an affidavit needs to tell the whole truth in their affidavit, or just give the relevant information that favours their case.

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The courts have been clear that people swearing affidavits should be careful to tell the whole truth in their affidavits, and to avoid creating a misleading situation by omitting relevant information which shows the true story.

The leading case about this in Australia is Re Thom [1918] NSWStRp 4; (1918) 18 SR (NSW) 70. In that decision the High Court condemned the practice of telling half truths by the “conscious withholding of information which[…] would be desirous of knowing in order to do justice to all parties.” Griffith CJ, with whom Gordon and Ferguson JJ agreed stated:

It is of the greatest importance that any mere casuistry in the presentation of evidence should be strictly avoided by those entrusted with the responsible duties of a legal practitioner. It is perhaps easy by casuistical reasoning to reconcile ones mind to a statement that is in fact misleading by considering that the deponent is not under any obligation to make a complete disclosure. By this means a practitioner may be led into presenting a statement of facts which, although it may not be capable of being pronounced directly untrue in one particular or another, still presents a body of information that is misleading, and conceals from the mind of the tribunal the true state of fact which the deponent is professing to place before it. For that reason it is proper on such an occasion as this to express condemnation of any such casuistical paltering with the exact truth of the case.

More recently, in ERS Engines Pty Ltd v Wilson (1994) 35 NSWLR 193 Young J said it was “completely unacceptable” for a witness “to only give the court a half truth.” Young J stated:

It cannot be emphasised too greatly that one’s obligation in making an affidavit is the same as when one is giving evidence in the witness box. One is to tell the truth and the whole truth.

The decision of Young J in ERS Engines has been subsequently cited several times with approval by the New South Wales Supreme Court. In Maio v Sacco [2009] NSWSC 413 White J cited ERS Engines and said:

It bears repetition that in swearing or affirming an affidavit a witness says that the affidavit contains not only the truth, but the whole truth and nothing but the truth.