The defence secretary is to announce details of how the Army will be restructured as it loses a fifth of its personnel over the next few years.
Philip Hammond will reveal the units to be scrapped or merged as the number of soldiers is cut from 102,000 to 82,000.
The Army 2020 review is also expected to result in the number of reservists doubling to 30,000.
Former head of the Army, Lord Dannat