However, it remains on course to meet its financial expectations for 2013, with a modestly increased order book.
Costain shareholders will be told today at the company’s annual general meeting that the group has had a strong start to the current year and is performing in line with the board's expectations.
The order book has increased to £2.5bn, up from £2.4bn at the start of the year, of which more than 90% is repeat orders. The preferred bidder position has grown from £400m to more than £500m in the same period.
To date, more than £800m of revenue has been secured for 2013 and the overall level of tendering activity across the group's targeted markets remains high, the directors report.
Having been outbid by Kier for May Gurney, Costain’s proposed merger is expected to officially lapse on 29 May 2013. Transaction costs of approximately £4m (pre-tax) were incurred chasing a deal and these will be expensed in the first half results and treated as a one-off non trading item.