Purpose

To distil the key practical principles from Unicomb v Blais regarding when the Harman undertaking (implied obligation) applies to affidavits and when parties may use such material in subsequent proceedings.

1. Core Holding on the Harman Undertaking

The Court held that the Harman obligation did not apply to the three affidavits.

Reason:
The affidavits were voluntarily filed pursuant to ordinary timetabling orders, which do not constitute compulsion in the sense required by Hearne v Street.
Compulsion is the threshold requirement.

“The need to find ‘compulsion’… conditions the types of material to which the principle applies… It is not enough to simply conclude that a document disclosed is an affidavit.”

2. The Court’s Test - Compulsion Is Essential

Compulsion must arise from the court process itself, for example:

• Discovery obligations;
• Subpoenas;
• Specific orders requiring disclosure of particular information; and
• Rules requiring particular affidavits on particular topics.

Not compulsion:

• Filing evidence under general evidence timetables;
• Strategic or ethical obligations to progress litigation; and
• Executors’ fiduciary duties.

The key question:
Was the party forced to disclose the specific information?

Here, because the affidavits were entirely voluntary and not mandated in content, the implied obligation never attached.

3. Distinction Between Affidavits and Witness Statements

The Court endorsed Brereton J’s analysis in Helicopter Aerial:

• Witness statements may retain confidentiality until deployed.
• Affidavits are inherently formal evidence, sworn to be read in open court and not confidential documents by nature.

Thus, inclusion of “affidavits” in Hearne v Street must be read with the compulsion requirement.

4. Treatment of Prior Authorities

The Court undertook detailed reconciliation of authorities:

• Central Queensland Cement and Springfield Nominees:
  Their broad principle (“document furnished for one purpose cannot be used for another”) is not the Hearne principle and cannot displace the compulsion requirement.
• Medway and Addstone:
  Applied Harman because disclosure was compelled.
• Silverstein (VSCA), Frigger, Helicopter Aerial, Woods, Stokes:
  All correctly focus on whether the specific documents were compelled.

McGrath J held none of the cited authorities established that affidavits filed under routine timetables are automatically subject to the undertaking.

5. Alternative Holding - Leave Would Have Been Granted

Even if Harman applied, the Court would still have released the parties from the undertaking.

Key reasons:

• Affidavits are expected to be read in open court;
• No personal or commercial sensitivity justifying restraint;
• Deponents identified no real prejudice;
• Significant relevance to issues in the new proceeding (authority of Gregory, agency, oral representations);
• Plaintiffs’ solicitor already possessed the documents legitimately from acting for Marie in the earlier matters; and
• Justice required permitting cross‑checking and potential impeachment.

This reinforces a pro‑release approach where documents are:

• Voluntarily produced;
• Intended to be evidence; and
• Relevant to achieving justice in subsequent proceedings.

6. Practical Implications for Litigators

A. Affidavits filed under standard evidence timetables are generally not protected by Harman.

Unless a court order requires specific disclosure, counsel may treat such affidavits as not subject to implied obligations.

B. When in doubt, seek declaration or leave.

As done here, an effective risk‑management tool.

C. Prior evidentiary material obtained in earlier matters may often be used in later proceedings without breach.

D. Solicitors who possess documents from prior matters must consider whether they acquired them under compulsion-this determines whether Harman applies.

7. Final Position

The Court declared the affidavits not subject to the Harman obligation and ordered the defendants to pay costs.

For more information about building and construction, commercial litigation and equity disputes, contact David Collins in the Mullane Lindsay litigation team.

Liability limited by a scheme approved under Professional Standards Legislation