EAIG13500 - Best judgement: partial breach of best judgement

In the case of Pegasus Birds [2004] EWCA Civ 1015 heard in the Court of Appeal Carnwath J, ruled that even if one aspect of an assessment is not made to best judgement this should not automatically invalidate the whole assessment. Carnwath J offered the following guidance to tribunals

Even if it is established that there has been a breach of the ‘best of their judgement’ requirement in relation to some element of the assessment, it does not follow in my view that the whole assessment should be set aside…

Where however, the complaint in substance is not against the assessment as such, but it is that the amount has not been arrived at by ‘best of their judgement’, I see nothing in the statute or in principle which requires the whole assessment to be set aside…

In my view, the tribunal, faced with a ‘best of their judgement’ challenge, should not automatically treat it as an appeal against the assessment as such, rather than against the amount.

Even if the process of assessment is found defective in some respect applying the Rahman (2) test, the question remains whether the defect is so serious or fundamental that justice requires the whole assessment to be set aside, or whether justice can be done simply by amending the amount…