| Investment in subsidiaries | 2007 £m |
2006 £m |
|
| Cost | |||
| At 1 January | 711.2 | 711.1 | |
| Additions | 0.2 | 0.1 | |
| At 31 December | 711.4 | 711.2 | |
| Provision for impairment | |||
| At 1 January | 396.2 | 396.1 | |
| Current year provision | 0.2 | 0.1 | |
| At 31 December | 396.4 | 396.2 | |
| Net book amount | |||
| At 1 January and 31 December | 315.0 | 315.0 |
Details of the Company’s principal subsidiaries are provided in Note 45 of the Consolidated Financial Statements.
The Directors also review at each year end the carrying value of the fixed asset investments. This review (undertaken by calculating value in use) did not result in the need for any impairment provision to be recognised as at 31 December 2006 or 31 December 2007.
In determining the value in use, the Directors calculated the present value of the estimated future cash flows expected to arise using post-tax discount rates based upon the Group’s weighted average cost of capital. Estimated future cash flows are based on management’s five-year plans for each investment, with extrapolation thereafter based on long-term average nominal growth rates of 4.0%.
