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
A campaign is underway to prevent a young Afghan refugee who's made a new life here being deported back to his own country.
The life of the three times Formula 1 World Champion Sir Jack Brabham has been celebrated at Silverstone.
Any remaining outbreaks of rain will clear during the rest of today to leave a fine weekend.