The firm also announced that Morrison's international business, which it is in the process of winding down, had lost £7.1m during the year on turnover of only £11.9m.
AWG has not started any new projects since it bought Morrison in August 2000. The Morrison losses contributed to AWG posting a post-exceptional loss of £53m.
AWG's troubles with Morrison have led to speculation that the group will sue former owners Gordon and Sir Fraser Morrison. AWG has refused to rule out the possibility of action. A spokesperson said: "Our legal investigation is entering its closing stages."