Turnover is measured at the fair value of consideration received or receivable, net of discounts and value added tax, and represents revenue from the rendering of services. Revenue is recognised by reference to the stage of completion of the contract, measured by comparing costs incurred to date with total estimated costs. Where the outcome cannot be measured reliably, revenue is recognised only to the extent of recoverable expenses.

Foreign currency transactions are translated into the functional currency using the spot exchange rates at the dates of the transactions. At each period end foreign currency monetary items are translated using the closing rate. Non-monetary items measured at historical cost are translated using the exchange rate at the date of the transaction and non-monetary items measured at fair value are measured using the exchange rate when fair value was determined.

Current tax is recognised in profit or loss, except for taxes related to revaluations of land and buildings which are recognised in other comprehensive income.

Current tax represents the amount of tax payable (receivable) in respect of taxable profit (loss) for the current, or past, reporting periods. Current tax is measured at the amount expected to be paid (recovered) using the tax rates and laws which have been enacted, or substantively enacted, by the balance sheet date. Where payments to HM Revenue and Customs exceed liabilities owed, an asset is recognised to the extent of the amount of tax recoverable.

Deferred tax is recognised in respect of all timing differences between the recognition of income and expenses in the financial statements and their inclusion in tax assessments. Unrelieved tax losses and other deferred tax assets are recognised only 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 and that are expected to apply to the reversal of the timing difference, except for revalued land and investment property where the tax rate that applies to the sale of the asset is used. Current and deferred tax assets and liabilities are not discounted.

Investments in subsidiaries, associates, and joint ventures are measured at cost less any accumulated impairment losses. Other investments in equity instruments that are publicly traded are measured at fair value, with changes in fair value recognised in the income statement. Other investments in equity instruments that are not publicly traded are measured at fair value unless this cannot be measured reliably, in which case they are measured at cost less any accumulated impairment losses.