Written by Steven Barrie When a trustee makes a mistake in the post Pitt and Futter world In the past there were three remedies available to trustees when they made a mistake. These were: (i) rectification; (ii) equitable relief for mistaken voluntary transactions; and (iii) relief from decisions which were not a breach of trust under the Hastings-Bass rule. These were often used together, with claims under the Hastings-Bass rule being run as an alternative to rectification and relief from mistakes as an alternative to Hastings-Bass. This note however focuses on the latter two remedies. The rule in Hastings-Bass was often used by trustees as a way of undoing transactions where unanticipated tax consequences became apparent. The rule in Hastings-Bass provided that where trustees exercised a discretion and the effect of this exercise differed from their intention, either because they failed to take into account relevant considerations or because they took into account irrelevant considerations, then provided it could be shown that the trustees would not have acted in the way they did had they only taken into account relevant considerations then the court would intervene to set aside the transaction. This meant that where trustees had not considered the tax consequences of the transaction, or had received inaccurate tax advice or implemented the advice erroneously, the transaction would be set aside. This was viewed by some as a soft option upon which trustees  could rely when they had made a mistake. It was not necessary to show a breach of trust and where the trustee had exercised discretion based upon  a mistake as to a material consideration, the exercise of the discretion was considered a nullity in equity. This was felt to be affording trustees [...]