9. Cash and cash equivalents

The group has cross undertaking guarantee facilities across certain bank accounts which allow a legally enforceable right of set off of the relevant cash and overdraft balances on bank accounts included within each scheme. Included within overdrafts at 31 March 2008 were balances of £256 million (2007: £49 million) which had a legally enforceable right of set off against cash balances of £112 million (2007: £117 million). These balances have not been netted above as settlement is not intended to take place simultaneously or on a net basis.
     The credit rating of counterparties with which cash and cash equivalents were held ranged from AAA to A with Standard and Poor’s and Aaa to A with Moody’s in both 2008 and 2007. The majority of cash and cash equivalents are fixed rate financial assets held for periods ranging from one day to three months.