The UK today released on 2 June 2025 an ambitious defense review, reorienting its armed forces toward “warfighting readiness” to deter Russian aggression, Breaking Defense reports.
Although filled with dozens of recommendations, the Strategic Defence Review (SDR) is headlined by plans to acquire “up to” a dozen nuclear-powered attack submarines (SSN) under the trilateral AUKUS program, new investments in AI, long range weapons, cyber capabilities and a major warfighting concept inspired by lessons learned from the Ukraine war.
“We are moving to warfighting readiness, as the central purpose of our armed forces. When we are being directly threatened by states with advanced military forces the most effective way to deter them is to be ready,” Prime Minister Keir Starmer said earlier today at BAE Systems Govan shipyard in Scotland and ahead of the formal launch of the strategic document [The PDF is here].
Perhaps the biggest move in the review is the UK’s commitment to acquire 12 AUKUS submarines for the Royal Navy, meant to replace seven Astute-class attack platforms. (Australia has said it intends to take on eight AUKUS subs, meaning the future fleet will consist of at least 20 boats.)
In a Sunday statement, the UK MoD did not share any costs associated with acquiring the 12 submarines, but said they are due to be in service “from the late 2030s,” while also disclosing a £15 billion ($20.3 billion) investment in “sovereign” nuclear warheads.
“Both the UK’s sovereign warhead programme and the UK’s conventionally-armed submarine fleet will make Britain and NATO safe for decades to come,” the MoD added. The UK’s Continuous At Sea Deterrent (CASD) is provided by Royal Navy Vanguard-classnuclear-powered ballistic missile submarines (SSBNs), with a program underway to develop the future Dreadnought-class.
The review also recommends expanding the UK’s contribution to NATO’s nuclear deterrence umbrella, shared by allies. Though it does not set out any specific potential solutions, talks between the UK and the Pentagon over orders of F-35A fifth-generation fighter jets and B61-12 tactical nuclear bombs are said to have been opened, according to the UK Sunday Times newspaper.
Should such deals be finalized, the UK would operate a second nuclear delivery platform, behind its CASD. “More F-35s will be required over the next decade,” states the review. “This could comprise a mix of F-35A and B models according to military requirements to provide greater value for money.”
The long-awaited review was originally commissioned by UK Prime Minister Kier Starmer in July 2024 and backed by a pledge to deliver a “new era” of defense, based around a “clear-eyed” approach to international threats, reforming “hallowed out” armed forces and a vow to end wasteful procurements.
Assessing the SDR as a whole, Malcolm Chalmers, deputy director general of the Royal United Services Institute, UK defense thinktank, told reporters that it is potentially the “most radical” of its kind for a “generation,” and as it ought to be, chiefly because the Ukraine war and Trump’s second term demands rethinking “a lot of the assumptions which have driven our defense” in the past.
The SDR did not dive deeply into the future of the UK’s surface fleet, but highlighted the need to “engage with commercial partners — including private finance — and other Governments to rapidly deliver an integrated frigate force for anti-submarine warfare.” (A Times report earlier had referred to the Royal Navy wanting to increase its frigate and destroyer fleet to 24 ships but such a ship count is not part of the document.)
Additionally, SDR urges the service to develop hybrid carrier airwings “whereby crewed combat aircraft (F-35B) are complemented by autonomous collaborative platforms in the air, and expendable, single-use drones.” Long-range missiles should also be part of the future airwings plan.
The strategic document includes a new underwater surveillance programme, dubbed Atlantic Bastion, due to be overseen by the service as a means to prevent Russian sabotage of subsea internet cables. It additionally calls for defensive shields to protect against enemy ballistic missile attacks, alongside a recommendation regarding the formation of a civilian home guard to safeguard national infrastructure.
Elsewhere, the SDR outlines a new way forward for British Army warfighting based around a drone-centric 20-40-40 strategy where uncrewed systems are deployed for first wave attacks, before tanks, attack helicopters and other crewed platforms arrive on the battlefield.
At a granular level, the figures see 20 percent of capability devoted to heavy weapon systems like Challenger 3 main battle tanks, 40 percent reserved for “single use” munitions such as one way attack drones or artillery shells and the other 40 percent aligned to larger tactical and strike capable drones, which include US-made MQ-9 aircraft.
The aim, the review said, is to “create a British Army which is 10x more lethal to deter from the land,” although it does not put forth a timeframe for such an ambitious transformation.
Taking stock of the troubled RAF E-7 Wedgetail airborne early warning and control aircraft program, the review recommends ordering more of them once funding allows but also puts forward alternative “opportunities for cost-sharing with NATO Allies” that hints at a joint procurement. However, other lucrative procurements like the £1 billion New Medium Helicopter do not feature at all, despite the MoD vowing to make a contract award this year. Leonardo is the only competitor left in the program after Lockheed Martin and Airbus both walked away.
Another thing the review does not do is raise UK defense spending above an already announced plan to hit 2.5 percent of GDP by 2027 and 3 percent by 2034. That jump would still fall short of an expected NATO effort to secure an agreement from all allies to spend up to 5 percent GDP, with 3.5 percent GDP on “core” capabilities and a further 1.5 percent on security related investments like infrastructure and cyber security.
A meeting of NATO defense ministers later this week could lead to an agreement on the two-tier spending plan.
7,000 Long Range Weapons, Munitions To Match
Another pillar of the strategy is a plan to spend £1.5 billion ($2 billion) on 7,000 long range weapons and “at least” six new munitions and energetics factories. The move fits in with supporting recommendations to establish an “always on pipeline” for munitions manufacturing and increase weapons stockpiles.
The new uptick in spending increases total expenditure on munitions to £6 billion over “this Parliament,” or approximately through 2028. Details about the additional long-range weapons and future production facilities, ranging from specific weapons to be produced, timeline for the sites to start operations and industry partners were not shared.
Despite the initial lack of detail surrounding the munitions commitments, Breaking Defense has since learned that a mix of highly capable and cheap weapons to increase mass are planned to be acquired. They could ease analyst concern over UK readiness.
“The UK must increase its production and procurement of munitions and complex guided weapons, not only to ensure it can fight a peer war and win, but also to give its deterrence posture credibility,” said a 2022 RUSI report.
In a separate move before release of the SDR, the UK also said it is investing £1 billion for a “Digital Targeting Web” capable of speeding up decision times for tracking and prosecuting targets, alongside a plan to stand up a Cyber and Electronic Command, which will be added to UK Strategic Command.
“This pioneering digital capability [Digital Targeting Web] will give the UK a decisive advantage through greater integration across domains, new AI and software, and better communication between our Armed Forces,” added the MoD in a statement, explaining that the Cyber and Electronic Command “will lead defensive cyber operations and coordinate offensive cyber capabilities with the National Cyber Force.”
A timeline for the introduction of the future command was not shared. “UK military networks” have faced more than 90,000 “sub-threshold” attacks over the last two years, according to the MoD.
