Financial risk factors
Our key financial risk factors are market risks, such as foreign exchange, transaction and translation exposures, and credit and liquidity risks. Please refer to of the financial statements for a discussion of these risk factors.
Off balance sheet arrangements
In the ordinary course of business, to manage our operations and financing, we enter into certain performance guarantees and commitments for capital and other expenditure.
The aggregate amount of indemnities and other performance guarantees, on which no material loss has arisen, including those related to joint ventures and associates, was £1 million at 31 March 2011 (2010 – £13 million).
We aim to optimise financing costs in respect of all financing transactions. Where it is economically beneficial, we choose to lease rather than purchase assets. Leases of property, plant and equipment where the lessor assumes substantially all the risks and rewards of ownership are treated as operating leases, with annual rentals charged to the income statement over the term of the lease. Commitments under operating leases to pay rentals in future years totalled £173 million
(2010 – £195 million) and related primarily to railcar leases in the USA. Rental charges for the year ended 31 March 2011 in respect of continuing operations were £23 million (2010 – £24 million).