The charge for taxation takes into account taxation deferred as a result of timing differences between the treatment of certain items for taxation and accounting purposes. In general, deferred taxation is recognised in respect of timing differences that have originated but not reversed at the balance sheet date. However, deferred tax assets are recognised only to the extent that the directors consider that it is more likely than not that there will be suitable taxable profits from which the future reversal of the underlying timing differences can be deducted. Deferred taxation is measured on a non-discounted basis at the tax rates that are expected to apply in periods in which the timing differences reverse, based on tax rates and the law enacted or substantively enacted at the balance sheet date.