Sinking feeling for the Royal Navy

Numbers of personnel will fall by 5,000 to around 30,000 by 2015 and 29,000 by 2020.

It will be equipped with 19 frigates and destroyers – down from 23 at present – to protect a naval task group which the review says will "meet our standing commitments at home and overseas". These will include six new Type 45 destroyers and new Type 26 frigates.

Work to build two new aircraft carriers will go ahead but only one of HMS Elizabeth or HMS Prince of Wales will enter service. One will be placed on extended readiness or sold.

Ministers said the carrier would give the UK political and military flexibility in responding to crises. It will be converted to allow French and United States aircraft to fly from it – delaying its expected in-service date until 2020 – and routinely carry 12 US-built Joint Strike Fighters, rather than the 36 originally envisaged.

Fitting catapult arrestor gear – known as "cat and trap" – will allow Britain to buy the cheaper version of the fighter without short-take off and vertical landing capability. The aircraft will have a 700-mile range over land and sea to carry out a broad range of missions. Helicopters will be embarked for operations.

Following the decommissioning within months of the flagship HMS Ark Royal and her fleet of Harrier jump jets, Prime Minister David Cameron admitted this would leave a capability gap in carrier strike capacity which had been the "most difficult decision for the Government to take" but he claimed air-to-air refuelling and fast jets meant Britain could still deploy around the world.

Also decommissioned will be either the helicopter landing ship HMS Ocean or HMS Illustrious following a study to examine which will provide the most effective helicopter platform capability.

Four other frigates and an amphibious support ship will also be decommissioned, numbers of re-supply and refuelling vessels scaled down to meet requirements and the Royal Navy estate rationalised.

Ministers said the smaller force would provide military flexibility and choice across a variety of operations from "full-scale warfare, through coercion and reassurance, to presence and maritime security, in particular protecting trade and energy supplies".

Seven new Astute Class hunter-killer nuclear-powered submarines will contribute to the protection of the nuclear deterrent and naval task groups.

In addition, The Royal Marines' 3 Commando Brigade will provide one element of a high readiness response force, able to "land and sustain a Commando Group of up to 1,800 personnel by helicopter and landing craft with protective vehicles, logistics and command and control support from a specialist landing and command ship".

The review said the Navy would ensure maritime defence of the UK and our overseas territories, including the South Atlantic and provide a "credible and capable presence within priority regions of the world that contributes to conventional deterrence, coercion and containment". Jane's Strategic Advisory Services consultant David Black said Harriers were expensive due to the advanced technology required to enable the aircraft to land on a ship's deck and the costs involved in building and maintaining them to withstand the corrosive effects of sea spray.

Carriers fitted with catapults would allow "cheaper, more conventional" naval aircraft such as the F35C to be used, he said.