A number of provinces have codified the implied undertaking:
Ontario: Rules of Civil Procedure, R.R.O. 1990, Reg. 194, r. 30.1.01;
Manitoba: Queen’s Bench Rules, M.R. 553/88, r. 30.1;
Prince Edward Island: Rules of Civil Procedure, r. 30.1.01.
Those statutes, which all have similar wording, create a “deemed” undertaking rule i.e. the undertaking is deemed to apply upon information being disclosed on discovery. Relevant wording of the Ontario Rule includes the following:
All parties and their lawyers are deemed to undertake not to use evidence or information to which this Rule applies for any purposes other than those of the proceeding in which the evidence was obtained.
(Rule 30.1.01(3), Rules of Civil Procedure, R.R.O. 1990, Reg. 194).
Subsection (4) of Rule 30.1.01 provides that the undertaking does not apply:
if the person who disclosed the information consents,
to evidence filed with the court, or
to evidence given or referred to during a hearing.
Subsection (8) of Rule 30.1.01 codifies the courts discretion to order that the implied undertaking does not apply in particular cases.
The rules also provide that the deemed undertaking rule “does not prohibit the use of evidence obtained in one proceeding, or information obtained from such evidence, to impeach the testimony of a witness in another proceeding”. This is a codification of the common law rule that an exception to the implied undertaking rule applies for the purposes of impeaching inconsistent testimony: see discussion below.
The case of T1T2 Limited Partnership v. Canada (Attorney General) (1996), 48 C.P.C. (3d) 84, 3 O.T.C. 127 (Gen. Div.) indicates that the common law implied undertaking still exists independently of the deemed undertaking rule. See also Goodyear v. Meloche (1996), 50 C.P.C. (3d) 398, 41 C.B.R. (3d) 112, 2 O.T.C. 174 (Gen. Div.).