The question what constitutes an "annuity" for the purpose of income tax laws has been the subject of much judicial decision without any clear or satisfactory test emerging. In England "any annuity or other annual payment" is chargeable under r. 1 (a) of the Rules applicable to Case III. of Schedule D of the Income Tax Act 1918 Imp. (8 & 9 Geo. 5 c. 40). That provision goes back substantially in its present form to the Act of 1853 and in other forms almost to the beginning of income tax: cf. per Lord Macnaghten, London County Council v. Attorney-General [1] . In deciding whether annual payments form an annuity the difficulty has been to find a satisfactory test for distinguishing between periodical instalments by way of payment or repayment of a capital sum and a fixed sum by way of income terminating at a time certain or on an uncertain event, as on the death of the payee. Yet such an income annuity may be purchased by a capital payment. In Scoble v. Secretary of State for India [2] Vaughan Williams L.J., whose judgment was approved in the House of Lords [3] , said: - "It could not be said that every annual sum payable on a contract was necessarily an annuity within the Income Tax Acts. It had to be admitted that, in any case in which it appeared on the face of the contract that there was a debt existing of such a nature that it could be said that the contract was not to purchase an annuity, but a contract under which a debt was made payable by instalments, in such a case the Income Tax Acts would not apply to the whole sum payable by such annual instalments". There the Secretary of State, having purchased the Indian Railway, had an option, instead of paying the value in a gross sum, to pay what was called an annuity for a term of years, the annuity being ascertained in a prescribed manner and being payable to annuity trustees. "The method of payment provided by the clause was in substance and in fact the payment of the price by means of half-yearly instalments, each of such instalments being composed in part of capital and, as to the residue, of interest on the amount of the price for the time being unpaid" [1] . Notwithstanding the use of the description "annuity", the payments, except in so far as they represented interest, were held to be but instalments of the capital price and therefore not within Case III. Lord Lindley said [2] : - "The annuity in this case is to my mind proved to demonstration to be nothing more than the payment by equal instalments of the purchase-money for the railway with interest." In Chadwick v. Pearl Life Insurance Company [3] Walton J. said: - "It is obvious that there will be cases in which it will be very difficult to distinguish between an agreement to pay a debt by instalments, and an agreement for good consideration to make certain annual payments for a fixed number of years. In the one case there is an agreement for good consideration to pay a fixed gross amount and to pay it by instalments; in the other there is an agreement for good consideration not to pay any fixed gross amount, but to make a certain, or it may be an uncertain, number of annual payments. The distinction is a fine one, and seems to depend on whether the agreement between the parties involves an obligation to pay a fixed gross sum."