C.I.R. v. Lo and Lo, [1984] B.T.C. 281 (PC) -- summary under Timing

Each long-term employee of a law firm was entitled, upon retirement, to a lump-sum payment from the firm roughly equivalent to 1/24 of his annual salary as at the date of retirement multiplied by the number of his years of service. The firm's accrued liability to date for future staff retirement benefits, calculated in this fashion, was held to be "an expense incurred" because under such an arrangement "the right of the employee to receive his retirement benefit is absolute, in the sense that he need do nothing whatever except give a period of notice and pick up his money." (Inland Revenue Ordinance of Hong Kong, s. 16).