The British Army is to axe some 20,000 troops as it undergoes a "fundamental restructuring" that is aimed at making the force "more flexible and agile".
Defence secretary Philip Hammond told the House of Commons that the number of regular soldiers will fall from the current strength of 102,000 to 82,000, Xinhua reported.
He added that reservists will double to 30,000 as part of the Army 2020 plan.
Hammond said now was a good time to plan cuts as Britain's combat role in Afghanistan was coming to an end in 2014.
He said the British Army will now be divided into two parts -- reaction forces and adaptable forces.
"The reaction forces will generate high-readiness, contingent capability, trained and equipped to undertake the full spectrum of intervention tasks, including provision of forces for the first phases of any future brigade-scale enduring operation," he said.
Hammond announced that the 2nd Battalion the Royal Regiment of Fusiliers, the 2nd Battalion the Yorkshire Regiment, 3rd Battalion the Mercian Regiment, and the 2nd Battalion the Royal Welsh Regiment will be axed.
"After a decade of enduring operations, we needed to transform the army and build a balanced, capable and adaptable force. Army 2020 will create a more flexible and agile army," he said.