All three of Britain's armed forces would take cuts in manpower. Overall, the largest overseas deployment was expected to be not more than 30,000 personnel, including maritime and air force units. This compares to the 45,000 involved in the 2003 invasion of Iraq. In November 2010, the MoD released its plan to implement the changes.
Royal Navy
Personnel to be reduced by 5,000 to 30,000.
One of the Albion class landing platform dock ships to be in extended readiness at any given time. Later confirmed that would be put into extended readiness until 2016, and went into extended readiness thereafter.
Either or to be decommissioned, whichever is least capable as a helicopter carrier. It was announced in December 2010 that would be retained and would be withdrawn from service in 2014.
One of the landing ship dock vessels would be decommissioned. The Bay-class landing dock was subsequently sold to the Royal Australian Navy in January 2011 for £65 million.
The number of warheads carried on each submarine to be reduced from 48 to 40, and the number of operationally available nuclear warheads to be reduced from about 160 to no more than 120.
The decision on replacement of the UK's nuclear deterrent, based on the Vanguard-class ballistic missile submarines, to be delayed by four years, deferring £500 million in spending. Changes to the size of the missile tubes to save £250 million.
Seven submarines to be built as planned.
The surface fleet of frigates and destroyers to be reduced to 19 ships: the current 13 Type 23 frigates and the six active Type 45 destroyers. The remaining four Type 22 frigates: 2011, 2011, 2011, and 2011 and five Type 42 destroyers: 2011, 2011, 2012, 2012, and 2013 would be disposed of "as soon as possible after 2020", and the Type 23 frigates would be replaced by new Global Combat Ships.
The Wildcat to be the main naval strike helicopter in the future, along with the Merlin.
The SDSR called for the almost immediate decommissioning of the Royal Navy flagship aircraft carrier,, rather than in 2016 as scheduled. This occurred on 11 March 2011. The Report also announced the early retirement of the Joint Force Harrier aircraft, the Harrier GR7/GR9. Both of these measures were to save money for the purchase of the aircraft carriers. The Harrier fleet made its last operational flights in December 2010. In 2011 72 British Harriers were sold to the United States to be used for spares. The SDSR proposed that one of the two Queen Elizabeth-class aircraft carriers currently under construction would be certain to be commissioned, with the fate of the other left undecided. It had been suggested that only one carrier, routinely equipped with 12 fast jets, was to be in service at any one time, with the other carrier held in extended readiness. These plans were to be reviewed in 2015. However, in May 2014 it was announced by Prime Minister David Cameron that the second carrier,, would be brought into service alongside. He confirmed the second vessel was already 40% built. The SDSR announced the government's intention to switch its purchase of F-35Bs to the carrier-variant F-35C to allow for a wider range and weapons to be used. However, in May 2012 this decision was reversed, and the F-35B was chosen instead, as the previous government had intended. This was because the cost of converting the Queen Elizabeth-class aircraft carriers to accommodate the carrier-variant F-35C had risen to twice the original estimate.
British Army
Personnel to be reduced by 7,000 to 95,500 by 2015. To take place within the overall mandate of reducing the army's size to 82,000 regular personnel and 30,000 reservists by 2018.
The withdrawal of all 20,000 British troops from bases in Germany by 2020.
The number of Challenger 2 tanks to be cut by 40% to just over 200.
The number of AS-90 self-propelled heavy artillery guns to be cut by 35% to an estimated 87.
Royal Air Force
Personnel to be reduced by 5,000 to 33,000.
After long delays, technical difficulties, and a total cost of £3.2 billion, the Nimrod MRA4maritime patrol aircraft project was scrapped. RAF Kinloss, where the aircraft were to be based, ended its 73-year association with the RAF on 26 July 2012 when it was transferred to the Army.
Future Strategic Tanker Aircraft procurement to go ahead, to replace the ageing VC10 and TriStars. The VC10 made its final flight in RAF service on 20 September 2013.
The C-130J fleet to be retired by 2022, ten years earlier than planned.
The proposed purchase of 12 additional Chinook helicopters – a cut to the original order for 22. However, in 2011 the Ministry of Defence signed a contract for 14 Chinooks.
The Sentinel R1 ground surveillance aircraft would be retired when it was no longer required to support forces in Afghanistan. The utility of the aircraft in deployments over Libya and Mali has led to some calls for the retention of the aircraft.
Criticism
On 3 August 2011, the House of Commons Defence Select Committee published a critical review of the SDSR. The review led to wide-ranging cuts to the Armed Forces, which were widely criticised for damaging the capabilities of the British military.
