Where an express trust is completely constituted, it is generally binding and irrevocable whether it was or was not constituted or declared for valuable consideration, unless a power of revocation is expressly reserved1.
A power to revoke the trust may be included within the trust instrument which may make an allowance for trustees, third parties, or even settlors to revoke the trust. However, if there is no power to revoke the trust, it is treated as an irrevocable disposition of property.
Strictly speaking a power to revoke is a power to recall, that is to revest the assets of the trust in the settlor; but the word “revoke” is sometimes used to mean terminate by distribution to the beneficiaries.
In Inland Revenue Commissioners v Saunders  AC 285, “terminate” was given the meaning “bring to an end” at 294 per Lord Reid.
In the case of a superannuation fund there may be a joint power to terminate held by jointly the Directors of the sponsoring employer and the trustees.
A power of revocation (or termination) must be exercised in accordance with the terms in which it conferred 2.
#1 – Ellison v Ellison (1802) 6 Ves 656; 31 ER 1243; Pulvertoft v Pulvertoft (1811) 18 Ves 84 at 99; 34 ER 249 at 254; Bill v Cureton (1835) 2 My & K 503 at 511; 39 ER 1036 at 1039; Collinson v Pattrick (1838) 2 Keen 123 at 134; 48 ER 575 at 579; Paul v Paul (1882) 20 Ch D 742; 47 LT 210, CA; Re Flavell (dec’d); Murray v Flavell (1883) 25 Ch D 89 at 102-3;[1881-85] All ER Rep 267 per Cotton LJ, CA Standing v Bowring (1885) 31 Ch D 282; [1881-85] All ER Rep 702; Trustee of the property of New, Prance & Garrard v Hunting  2 QB 19, CA; Radcliff v Abbey Road and St John Wood Permanent Building Society (1918) 87 LJ Ch 557.
#2 – Ellison v Ellison (1802) 6 Ves 656; 31 ER 1243 at 1247.Ellison v Ellison
This tab updated on 21 July 2015