Contractor Carillion's operating profit will fall £12m over the next two years because of changes to accounting procedures.
It will now write off pre-contract bid costs as they are incurred, rather than when the contract reaches financial close. The costs will then be recouped over the construction period of the contract.

Jarvis and Amey have already changed their accounting methods.

In a trading statement, Carillion said earnings per share for this year would not be affected by the changes. This is because of a lower-than-expected tax charge and increased savings from a restructuring programme last year.

Carillion added that it had secured £1bn worth of contracts in the first half.

The contractor announced that its subsidiary Carillion Services had won a £50m, seven-year contract to supply services to hospitals in Lincolnshire, the largest of its type.

BAA has also selected Carillion's M&E arm Crown House Engineering as one of two companies for a £200m, seven-airport contract.