for the year to 31 December 2007
| £m | |
| Cost and carrying amount | |
| At 1 January 2006 | 363.9 |
| Changes in exchange rates | (0.8) |
| At 31 December 2006 | 363.1 |
| Changes in exchange rates | (0.1) |
| Acquired on acquisition of George Wimpey Plc | 336.8 |
| At 31 December 2007 | 699.8 |
The Group tests goodwill annually for impairment or more frequently if there are indicators that goodwill might be impaired.
Goodwill of £694.3m (2006: £357.5m) is allocated to the UK Housing business. Goodwill of £5.5m (2006: £5.6m) is allocated to the US Housing business. The recoverable amount in respect of UK Housing has been determined on the basis of the business' value in use. The value in use is the present value of the future cash flows expected to be derived from the cash-generating unit over the next 20 years. Key assumptions used in the calculation are:
As a result of this review no impairment was recorded.