for the year to 31 December 2007
| 2007 | 2006 | |
| £m | £m | |
| Contracts in progress at the balance sheet date: | ||
| Amounts due from contract customers included in trade and other receivables | 57.3 | 65.2 |
| Amounts due to contract customers included in trade and other payables | (39.1) | (26.1) |
| 18.2 | 39.1 | |
| Contract costs incurred plus recognised profits less recognised losses to date. | 3,684.8 | 3,571.4 |
| Less: progress billings | (3,666.6) | (3,532.3) |
| 18.2 | 39.1 |
At 31 December 2007, retentions held by customers for contract work amounted to £11.1m (2006: £12.6m).