Notes to the consolidated financial statements – analysis of items in the primary statements

20. Cash and cash equivalents

  2008
£m
2007
£m
Cash at bank 93 50
Short-term deposits 81 1,543
Cash and cash equivalents excluding bank overdrafts 174 1,593
Bank overdrafts (10) (6)
Net cash and cash equivalents 164 1,587

The carrying amounts of cash and cash equivalents and bank overdrafts approximates their fair values.

Cash at bank earns interest at floating rates based on daily bank deposit rates. Short-term deposits are made for varying periods of between one day and three months, depending on the immediate cash requirements, and earn interest at the respective short-term deposit rates.

Net cash and cash equivalents held in currencies other than sterling have been converted into sterling at year-end exchange rates. For further information on currency exposures, refer to note 33.

National Grid USA and its public utility subsidiaries (all consolidated subsidiaries) are subject to restrictions on the payment of dividends by administrative order and contract. At 31 March 2008, £51m (2007: £132m) of cash and cash equivalents were restricted.