Shares
£m
Cost
At 1 January 2016401.7
Acquisitions16.3
Disposals(20.5)
At 31 December 2016397.5
Provision for impairment
At 1 January 20156.7
Disposals(0.1)
At 31 December 20166.6
Net book value
At 31 December 2016390.9
At 31 December 2015395.0