2. Net operating costs
| Year ended 31 December 2003 £m |
Year ended 31 December 2002 £m |
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| Excluding exceptional items: | |||
| Cost of sales | 729 | 558 | |
| Other operating costs | 64 | 85 | |
| Other operating income | (66) | (134) | |
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| Net operating costs | 727 | 509 | |
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| Other operating income includes compensation for the late commissioning of plant, billings in respect of operations and maintenance services and profits on sale of development sites. Exceptional items would increase cost of sales by £404 million (2002: £103 million). | |||