280 
SECRETARIAL PRACTICE 
(4) This section applies to payments and acts made 
and done before or after the commencement of 
this Act, and in this section ‘power of attorney’ 
includes a power of attorney implied by statute. 
Express A power of attorney, even though executed under seal, 
Revocation. may be revoked by parol [R. v. Wait (1823) 1 Bingh. 121]. 
In practice, however, express revocation by the donor should 
be effected by deed. It is also open to the donee to effect 
revocation by giving notice to the donor that he renounces 
the power. 
Implied The common law was thus laid down by Lord Blackburn in 
Revocation. Debenham v. Mellon (1880), 6 A.C. at p. 36: ‘Where an 
agent is clothed with an authority and afterwards that 
authority is revoked, unless the revocation has been made 
known to those who have dealt with him, they would be 
entitled to say: “The principal is precluded from denying 
that the authority continued to exist, which he had 
led us to believe, as reasonable people, did formerly 
exist.””’ 
But there is left the problem which dwells in those words 
in Lord Blackburn’s judgment (above)—‘as reasonable 
people.” The expression suggests at once that there is such a 
thing as implied revocation, and that the third party may 
be deemed to have constructive, as distinct from actual, 
notice of revocation. There are many circumstances which 
would be held to amount to such an implication, e.g. the 
appointment by the principal of another attorney—especially 
if the second attorney were invested with powers, the exercise 
of which would clash with the authority of the first; a lapse 
of time since the creation of the power, such as would lead 
any ordinary man to doubt the probability of its continued 
currency; the intervention of the principal himself in the 
conduct of the business for which the power had been origin- 
ally granted. Similarly, if a donor says that the attorney 
is to act only when he is himself prevented from acting, a 
third party may be at his wits’ end to know what to do. 
In all such cases the third party would be justified in requir- 
ing proof of the continuing validity of the power of attorney. 
The first paragraph of s. 124 (2), which is printed above in 
italics, enables the third party to obtain protection by requir- 
ing the attorney to make a statutory declaration as therein 
provided. Such a declaration, however, will not protect a 
third party who is in fact aware, of his own knowledge, that 
the power has been revoked [Mutual Provident Land Vv. 
Macmillan (1889), A.C. 596]