The Government is due to announce plans that will see five infantry battalions axed altogether and other units merged or turned into reservists in the biggest structural changes to the Army in more than a century.
The defence secretary, Philip Hammond will set out how the regular Army will be cut from 102,000 troops to 82,000 by the end of the decade - its lowest level since the Napoleonic Wars.
Sky News has obtained details of the five infantry battalions that are to be scrapped as part of Government cuts.
They are 5 Scots - The Argyll and Sutherland Highlanders, one battalion of The Yorkshire Regiment, 2nd Battalion The Royal Regiment of Fusiliers, 3rd Battalion The Mercian Regiment (The Staffords) and 2nd Battalion The Royal Welsh Regiment.
Sky's defence and security editor, Sam Kiley said: "While this is a cultural blow particularly to the people who have served in these units in the past, nowadays they are part of bigger regiments in any case.
"Where the controversy will lie is with the Royal Regiment of Fusiliers and The Royal Welsh because they will be down to one battalion regiment."
The plan - known as Army 2020 - is expected to see the military split into two, with a reaction force, ready to respond to emergencies around the globe, and an adaptable force capable of carrying out a range of tasks and commitments.
Mr Hammond has said the changes - drawn up by Lieutenant General Nick Carter - will provide the basis of a smaller, more flexible and agile Army into the future.
But the prospect of losing historic units has been the cause of intense anguish within the service.
Kiley adds: "Back in 2006, the whole idea of the amalgamations that we saw then was that the army did not end up with single battalion regiments that were unwieldy and very difficult to bring good officers and good men on because they got stovepiped in this one institution."
The Daily Telegraph disclosed this week that one officer, Brigadier David Paterson of the Royal Regiment of Fusiliers, had written to the head of the Army expressing his bitter disappointment at plans to axe one of its two battalions.
In his letter to General Sir Peter Wall, Chief of the General Staff, Brig Paterson said the proposal "cannot be presented as the best or most sensible military option".
Mr Hammond, who will set out details of the proposals in a statement to the House of Commons, has acknowledged that they have involved some "difficult" decisions.
But he said that cuts could not be avoided, with the demands for strict financial discipline under the Government's 2010 Strategic Defence and Security Review.
For the plans to be successful, reductions in regular Army strength will need to be offset by increases in part-time reservists, with the Territorial Army doubling in numbers from 15,000 to 30,000.
As well as providing specialist capabilities - such as medics and intelligence - reservists would be used to reinforce infantry battalions on deployment.
They will be expected to shoulder a third of the burden of long-term operations.
The Army would also be required to make greater use of civilian contractors in areas such as logistics support in order to concentrate military capability on the frontline.
