## (l) Trade and other receivables 

Trade and other receivables are recognised at amortised cost, less an allowance for doubtful debts. Trade receivables are generally due for settlement within 30 days. 

Collectibility of trade receivables is reviewed on an ongoing basis. An allowance for doubtful debts is recognised when there is objective evidence that the consolidated entity will not be able to collect all amounts due. Financial difficulties of the debtor, default payments or debts overdue are considered objective evidence of impairment. The amount of the allowance is the difference between the asset’s carrying amount and the present value of estimated future cash flows. 

The amount of the impairment loss is recognised in the income statement within other expenses. When a trade receivable is uncollectible, it is written off against the allowance account. Subsequent recoveries of amounts previously written off are credited against other expenses in the income statement. 

Unbilled revenue represents estimated gas and electricity services supplied to customers but unbilled at the end of the reporting period. 

## (m) Inventories 

Stocks and materials are valued at the lower of cost and estimated net realisable value. Costs, including an appropriate portion of fixed and variable overhead expenses, are assigned to inventory on hand by the method most appropriate to each particular class of inventory, with the majority being valued on a first-in-first-out basis. Finished goods includes gas inventory. 

## (n) Financial assets 

All financial assets are recognised and derecognised on trade date where the purchase or sale of a financial asset is under a contract whose terms require delivery of the financial asset within the timeframe established by the market concerned, and are initially measured at fair value, plus transaction costs, except for those financial assets classified as at fair value through profit or loss, which are initially measured at fair value. 

Financial assets are classified into the following specified categories: financial assets ‘at fair value through profit or loss’, ‘available-for-sale’ financial assets, and ‘loans and receivables’. The classification depends on the nature and purpose of the financial assets and is determined at the time of initial recognition. 

Financial assets at fair value through profit or loss Financial assets classified as held for trading are included in the category ‘financial assets at fair value through profit or loss’. Financial assets are classified as held for trading if acquired principally for the purpose of selling in the short-term. Derivatives are also classified as held for trading unless they are designated as effective hedging instruments. Gains or losses on financial assets held for trading are recognised in profit or loss and the related assets are classified as current assets in the statement of financial position. Fair value is determined in the manner described in Note 52. 

## Available-for-sale fi nancial assets 

Listed shares held by the consolidated entity that are traded in an active market are classified as available-for-sale and are stated at fair value. Fair value is determined in the manner described in Note 52. Gains and losses arising from changes in fair value are recognised directly in other comprehensive income and accumulated in the investments revaluation reserve, with the exception of impairment losses, which are recognised in profit or loss. Where the investment is disposed of or is determined to be 

impaired, the cumulative gain or loss previously accumulated in the investments revaluation reserve is reclassified to profit or loss. 

## Loans and receivables 

Loans and receivables are non-derivative financial assets with fixed or determinable payments that are not quoted in an active market. Loans and receivables are measured at amortised cost using the effective interest method, less any impairment. They are included in current assets, except for those with maturities greater than 12 months after the end of the reporting period which are classified as non-current assets. Loans and receivables are included in trade and other receivables and other financial assets in the statement of fi nancial position. 

## Impairment of fi nancial assets 

Financial assets, other than those at fair value through profit or loss, are assessed for indicators of impairment at the end of each reporting period. Financial assets are considered to be impaired where there is objective evidence that, as a result of one or more events that occurred after the initial recognition of the financial asset, the estimated future cash flows of the asset have been effected. 

For financial assets measured at amortised cost, the amount of the impairment loss recognised in profit or loss is the difference between the asset’s carrying amount and the present value of estimated future cash flows, discounted at the financial asset’s original effective interest rate. Impairment of trade receivables is recognised in accordance with the accounting policy set out in Note 1(l). When an available-for-sale financial asset is considered to be impaired, cumulative gains or losses previously recognised in other comprehensive income are reclassified to profit or loss. 

With the exception of available-for-sale equity instruments, if, in a subsequent period, the amount of the impairment loss decreases and the decrease can be related objectively to an event occurring after the impairment was recognised, the previously recognised impairment loss is reversed through profit or loss. 

In respect of available-for-sale equity instruments, impairment losses previously recognised in profit or loss are not reversed through profit or loss. Any increase in fair value subsequent to an impairment loss is recognised in other comprehensive income. 

## Derecognition of fi nancial assets 

Financial assets are derecognised when the rights to receive cash flows from the financial assets has expired or when the consolidated entity transfers substantially all the risks and rewards of the financial assets. If the consolidated entity neither retains nor transfers substantially all of the risks and rewards of ownership, it derecognises the asset if it has transferred control of the assets. 

## (o) Non-current assets and disposal groups held for sale 

Non-current assets and disposal groups are classified as held for sale if their carrying amount will be recovered principally through a sale transaction rather than through continuing use. This condition is regarded as met only when the sale is highly probable and the non-current asset or disposal group is available for immediate sale in its present condition. Management must be committed to the sale, which should be expected to qualify for recognition as a completed sale within one year from the date of classification. 

Non-current assets (including those that are part of a disposal group) are not depreciated or amortised while they are classified as held for sale. Non-current assets and disposal groups classified as held for sale are measured at the lower of their previous carrying amount and fair value less costs to sell. 

