On 27th January 1949 the taxpayer made his individual return which referred to the partnership return made on the same day. The taxpayer, not having received an assessment within a year from the making of a return, made a request for assessment pursuant to s. 171 of the Act and this was complied with on 6th April 1950. The individual return was dealt with in "the partner's sub-section" of the Office of the Deputy Commissioner of Taxation, New South Wales, and was dealt with as it stood and without reference to "the partnership sub-section" where the partnership return lay and where it was dealt with later. The officer of the Commissioner who was responsible for assessing the taxpayer made the assessment in accordance with instructions to assess upon the figures disclosed by the return and marked it "A.X.M." indicating that the assessor had no knowledge whether the individual interest of the taxpayer in the net income derived by the partnership had been ascertained in the partnership sub-section or of the amount of that individual interest if it had then been so ascertained and that the assessor did not refer to the return of income lodged by the partnership. The assessor also marked the taxpayer's return "A.O.F." and "review when partnership attached". The letters "A.O.F." are recognized in the Office as an abbreviation for the expression "Assess on figures" and the words "review when partnership attached" were endorsed by the assessor to indicate that the taxable income of the appellant as ascertained by him might require amendment upon the calculation of the appellant's individual interest in the net income of the partnership by the partnership sub-section. It was only when the partnership return was considered in the partnership sub-section that it was ascertained, mainly from the information supplied therewith, that the figures in the partnership return were incorrect. After some correspondence an amended assessment was issued on 18th April 1952, which was further amended on 4th January 1954 to include as the item of property income share in partnership G. W. and A. M. Lee the sum of £1,397. The taxpayer's objection, as has been already stated, was disallowed by the Board of Review by a majority on the ground, inter alia, that the amended assessment was made to correct a mistake of fact. It is the correctness of that decision that is now before the Court.