“(i) The best formulation of the principle seems to me to be this. Where trustees act under a discretion given to them by the terms of the trust, in circumstances in which they are free to decide whether or not to exercise that discretion, but the effect of the exercise is different from that which they intended, the court will interfere with their action if it is clear that they would not have acted as they did had they not failed to take into account considerations which they ought to have taken into account, or taken into account considerations which they ought not to have taken into account.”
“(v) I am in no doubt that, as a general proposition, fiscal consequences are among the matters which may be relevant for the purposes of the principle.”
“If the discrepancy between the intended and actual fiscal consequences were the result of a later court decision by which the position was held to be otherwise than had previously been supposed, it would be very surprising if that change could have the effect of invalidating acts by trustees done on the basis of the previous understanding of the position.”