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.
Freehold investment property is included at fair value within tangible fixed assets, changes in fair value are recognised in the profit and loss account. Deferred taxation is provided on the gains at the rate expected to apply when the property is sold.