“…Income tax is a levy on income. No doubt, the Income-tax Act takes into account two points of time at which the liability to tax is attracted, viz., the accrual of the income or its receipt; but the substance of the matter is the income. If income does not result at all, there cannot be a tax, even though in book-keeping, an entry is made about a “hypothetical income”, which does not materialise. Where income has, in fact, been received and is subsequently given up in such circumstances that it remains the income of the recipient, even though given up, the tax may be payable. Where, however, the income can be said not to have resulted at all, there is obviously neither accrual nor receipt of income, even though an entry to that effect might, in certain circumstances, have been made in the books of account…”