Accounting policies (Tables)

12 Months Ended

Dec. 31, 2017

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Estimated Useful Lives of Property, Plant and Equipment

Depreciation on other assets is calculated using the straight-line method to allocate their cost less their residual values over their estimated useful lives as follows:

Buildings (freehold):	20-50 years
Buildings (leasehold):	over the period of the lease
Plant and equipment:	3-10 years