Taxation Current tax is recognised on taxable profit for the current and past periods. Current tax is measured at the amounts of tax expected to pay or recover using the tax rates and laws that have been enacted or substantively enacted at the reporting date. Deferred tax is recognised in respect of all timing differences at the reporting date. Unrelieved tax losses and other deferred tax assets are recognised to the extent that it is probable that they will be recovered against the reversal of deferred tax liabilities or other future taxable profits. Deferred tax is measured using the tax rates and laws that have been enacted or substantively enacted by the reporting date that are expected to apply to the reversal of the timing difference. Impairment A review for indicators of impairment is carried out at each reporting date, with the recoverable amount being estimated where such indicators exist. Where the carrying value exceeds the recoverable amount, the asset is impaired accordingly. Prior impairments are also reviewed for possible reversal at each reporting date. When it is not possible to estimate the recoverable amount of an individual asset, an estimate is made of the recoverable amount of the cash-generating unit to which the asset belongs. The cash-generating unit is the smallest identifiable group of assets that includes the asset and generates cash inflows that are largely independent of the cash inflows from the other assets or groups of assets. Provisions Provisions are recognised when the entity has an obligation at the reporting date as a result of a past event; it is probable that the entity will be required to transfer economic benefits in settlement and the amount of the obligation can be estimated reliably. Provisions are recognised as a liability in the statement of financial position and the amount of the provision as an expense. Defined contribution plans Contributions to defined contribution plans are recognised as an expense in the period in which the related service is provided. Prepaid contributions are recognised as an asset to the extent that the prepayment will lead to a reduction in future payments or a cash refund.