Costain is to merge with May Gurney.
Costain earned pre-tax profits of about £26 million on revenues o f£930 million in 2012. May Gurney had revenues of about £700 million in its latest financial year, earning profits of #19.3 million.
Costain's existing shareholders will take 53% of the enlarged company, with May Gurney investors taking 47%.
The deal still needs the backing of both sets of shareholders.
More top news
Increasing cloud and rain overnight. Blustery and cold tomorrow.
Events are taking place in Cambridge, Norwich, Colchester, Southend and Lowestoft today, to mark Holocaust Memorial Day.
Cloud will increase through the day with rain arriving by dawn.