Other intangible assets are measured at cost less accumulated amortisation and any accumulated impairment losses. It is amortised to profit and loss account over its estimated economic life of 20 years.

Research and development expenditure is written off as incurred, except that development expenditure incurred on an individual project is capitalised as an intangible asset when the group can demonstrate the technical feasibility of completing the intangible asset so that it will be available for use or sale, its intention to complete and its ability to use or sell the asset, how the asset will generate future economic benefits, the availability of resources to complete the asset and the ability to measure reliably the expenditure during development. Following initial recognition of the development expenditure as an asset, the cost model is applied requiring the asset to be carried at cost less any accumulated amortisation and accumulated impairment losses. During the period of development the asset is tested for impairment annually.

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:

Monetary assets and liabilities in foreign currencies are translated into sterling at the rates of exchange ruling at the balance sheet date. Transactions in foreign currencies are translated into sterling at the rate ruling on the date of the transaction. Exchange differences are taken into account in arriving at the operating profit.

Government grants are recognised in the profit and loss account in an appropriate manner that matches them with the expenditure towards which they are intended to contribute.