Assets obtained under hire purchase contracts and finance leases are capitalised as tangible fixed assets. Assets acquired under finance leases are depreciated over the shorter of the lease term and their useful lives. Assets acquired under hire purchase contracts are depreciated over their useful lives. Finance leases are those where substantially all of the benefits and risks of ownership are assumed by the company. Obligations under such agreements are included in the creditors net of the finance charge allocated to future periods. The finance element of the rental payment is charged to the profit and loss account so as to produce a constant periodic rate of charge on the net obligation outstanding in each period.

Stocks and work in progress are valued at the lower of cost and net realisable value after making due allowance for obsolete and slow-moving stocks. Cost includes all direct costs and an appropriate proportion of fixed and variable overheads. Work-in-progress is reflected in the accounts on a contract by contract basis by recording turnover and related costs as contract activity progresses.

Monetary assets and liabilities in foreign currencies are translated into sterling at the rates of exchange ruling at the balance sheet date. Transactions in foreign currencies are translated into sterling at the rate ruling on the date of the transaction. Exchange differences are taken into account in arriving at the operating profit.