Shares
£m
Cost
At 1 January 2015400.0
Acquisitions2.7
Disposals(1.0)
At 31 December 2015401.7
Provision for impairment
At 1 January 20157.4
Provision in the year0.1
Disposals(0.8)
At 31 December 20156.7
Net book value
At 31 December 2015395.0
At 31 December 2014392.6