Income tax expense represents the sum of the tax currently payable and deferred tax.
The tax currently payable is based on taxable profit for the year. Taxable profit differs from profit as reported in the statement of comprehensive income because of items of income or expense that are taxable or deductible in other year and items that are never taxable or deductible. The company's liability for current tax is calculated using tax rates that have been enacted or substantively enacted by the end of the reporting period.
Deferred tax arises as a result of including items of income and expenditure in taxation computations in periods different from those in which they are included in the company's accounts. Deferred tax is provided in full on timing differences which result in an obligation to pay more (or less) tax at a future date, at the average tax rates that are expected to apply when the timing differences reverse, based on current tax rates and laws.
Deferred tax assets and liabilities are not discounted.