Investments in subsidiaries, associates and joint ventures are measured at cost less any accumulated impairment losses. Listed investments are measured at fair value. Unlisted investments are measured at fair value unless the value cannot be measured reliably, in which case they are measured at cost less any accumulated impairment losses. Changes in fair value are included in the profit and loss account.

Short term creditors are measured at transaction price (which is usually the invoice price). Loans and other financial liabilities are initially recognised at transaction price net of any transaction costs and subsequently measured at amortised cost determined using the effective interest method.

Equity-settled share-based payments are measured at fair value at the date of grant by reference to the fair value of the equity instruments granted using the Black Scholes model. The fair value determined at the grant date is expensed on a straight-line basis over the vesting period, based on the estimate of shares that will eventually vest. A corresponding adjustment is made to equity.