Tangible fixed assets are measured at cost less accumulated depreciation and any accumulated impairment losses. Depreciation is provided at rates calculated to write off the cost of the fixed assets, less their estimated residual value, over their expected useful lives on the following bases:
Assets under construction contain capitalised development expenditure, including interest costs on associated borrowings, incurred in bringing an asset to a usable state. If it is deemed no longer economically viable to develop an asset, the relevant capitalised costs would be written off. The gain or loss arising on the disposal of the asset is determined as the difference between the sale proceeds and the carrying value of the asset, and is credited or charged to profit or loss.
Fixed asset investments
Interests in subsidiaries, associates and jointly controlled entities are initially measured at cost and
subsequently measured at cost less any accumulated impairment losses. The investments are assessed for
impairment at each reporting date and any impairment losses or reversals of impairment losses are
recognised immediately in profit or loss.