The Commissioners may mitigate the effects of paragraph 20 in relation to a person (“P”) so far as it appears to them that there are exceptional circumstances such that the operation of that paragraph would otherwise have an unduly serious impact with respect to the tax affairs of P or another person.

For the purposes of sub-paragraph (1) the Commissioners may modify the effects of paragraph 20 in any way they think appropriate, including by allowing P access to the whole or part of a relief to which P would otherwise not be entitled as a result of paragraph 20.