TMA 1970, s 20(1)

(a) to deliver to him such documents as are in the person’s possession or power and as (in the inspector’s reasonable opinion) contain, or may contain, information relevant to –
(i) any tax liability to which the person is or may be subject, or(ii) the amount of any such liability, or
(b) to furnish to him such particulars as the inspector may reasonably require as being relevant to, or to the amount of, any such liability.]5

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