23 Trade and other payables

The average credit period taken for trade purchases is 34 days (2008: 29 days).
The directors consider that the carrying amount of trade payables approximates to their fair value at both 31 March 2009 and 31 March 2008.
Deferred grants and contributions

Deferred grants are those amounts received under government grant schemes. Deferred contributions are those amounts received from customers in respect of new connections to the network.