Other intangible assets
Intangible assets are stated at cost less provisions for amortisation and impairments.
Licences, patents, know-how and marketing rights separately acquired or acquired as part of a business combination are amortised over their estimated useful lives, generally not exceeding 20 years, using the straight-line basis, from the time they are available for use. The estimated useful lives for determining the amortisation charge take into account patent lives, where applicable, as well as the value obtained from periods of non-exclusivity. Asset lives are reviewed, and where appropriate adjusted, annually. Contingent milestone payments are recognised at the point that the contingent event becomes probable. Any development costs incurred by the Group and associated with acquired licences, patents, know-how or marketing rights are written off to the income statement when incurred, unless the criteria for recognition of an internally generated intangible asset are met, usually when a regulatory filing has been made in a major market and approval is considered highly probable.
Acquired brands are valued independently as part of the fair value of businesses acquired from third parties where the brand has a value which is substantial and long term and where the brands either are contractual or legal in nature or can be sold separately from the rest of the businesses acquired. Brands are amortised over their estimated useful lives of up to 20 years, except where it is considered that the useful economic life is indefinite.
The costs of acquiring and developing computer software for internal use and internet sites for external use are capitalised as intangible fixed assets where the software or site supports a significant business system and the expenditure leads to the creation of a durable asset. ERP systems software is amortised over seven to ten years and other computer software over three to five years.