Fixed asset investments comprise investments in subsidiary undertakings, as follows:

2015
£m
2014
£m
Cost
At 1 January650.2662.3
Disposals(12.1)
At 31 December650.2650.2
Accumulated impairment charges
At 1 January207.2216.2
Impairment charge3.1
Disposals(12.1)
At 31 December207.2207.2
Net book value
At 31 December443.0443.0
At 1 January443.0446.1

Details of the Company's subsidiaries are shown in Group Companies 2015.