Prime Minister Boris Johnson has been challenged by Labour leader Sir Keir Starmer to allow MPs to vote on a "cut" to the UK military.
Sir Keir said in the House of Commons: "Only this Prime Minister could suggest a reduction from 82,000 to 72,000 is somehow not a cut.
"What did he do this week? He cut the British Army by 10,000.
"He cut the number of tanks, he cut the number of planes for our RAF, and he cut the number of ships for the Royal Navy."
Sir Keir accused the Prime Minister of failing on a pledge that the military would not be cut "in any form", which Mr Johnson made in 2019.
"What's weaker than making a promise to our Armed Forces just before the election, then breaking it and not being prepared to admit it, not having the courage to admit it?" the Labour leader added.
The Prime Minister replied: "Not only did we keep our promise in the manifesto, we actually increased spending by 14% more than that manifesto commitment."
He also said the Army's total strength will be kept "at 100,000 if you include the reserves".
Watch: Defence Secretary Ben Wallace outlined the future plans for the military earlier this week.
Later, the Labour leader asked: "Why doesn't [the Prime Minister] at least have the courage to put this cut in the Armed Forces to a vote in this house?"
Mr Johnson replied, telling the Commons: "I'm proud of what we're doing to increase spending on the Armed Forces.
"We believe in defence, we've been getting on with the job."
He said: "This review won't end the era of retreat, in fact, it will extend it."
In addition to the Army's regular force being reduced, the Defence Command Paper revealed the service's structure is being reorganised and detailed changes in equipment.
Nine Royal Air Force Reapers are being replaced by Protector in the next three years, while three E-7 Wedgetails will take over from the outgoing E-3 Sentry, with tranche one Typhoons being retired by 2025.
The C-130J Hercules aircraft, meanwhile, is being retired in 2023, with the capability transitioning to the C-17 and A400M.
New automated minehunting systems will also be deployed in the future, replacing the Sandown and Hunt classes, which will both retire in the 2020s.