Centre for the Public Understanding of Defence and Security (CPUDS) - The UK Defence Investment Plan, 2026: the Return of the Walking Dead?
DefenceSynergia (DS) is grateful to CPUDS for allowing DS to publish their discussion paper entitled ‘The UK Defence Investment Plan, 2026: the Return of the Walking Dead?’.
This constitutes a series of 5 short essays written by expert authors as follows: Royal Navy by Peter Roberts; British Army by Paul Cornish; Royal Air Force by Philip Lester; The Cyber and Information Domains by Ewan Lawson and UK Defence Industry by Paul Hough. The Introduction and conclusions having been crafted by Paul Cornish.
This CPUDS contribution to the defence debate is most welcome given that this informed analysisreaches out to an arguably ill-informed British public at a time when His Majesty’s Government (HMG) is prevaricating over the funding of its own Strategic Defence Review 2025 (SDR25) and Defence Investment Plan.
DS agrees with all the essays but would go further by pointing out that HMG has still not produced a discernable articulated National Grand Strategy from which MOD and the Chiefs of Staff might draw for the Military Strategy that underpins their spending case.
What strategy there is seems to be ‘all things to all men’ – certainly in the Treasury.
DS asks: Does UK have a world wide role or not? Are our Overseas Territories (OTs) to be defended or not? Given the most recent closure of the Hormuz Strait and pressure on the Bab el-Mandeb Strait does UK retain a role defending sea lanes of communication (SLOC) or not?
As explained in the CPUDS analysis of the DIP, UK still has commitments to NATO, UN, AUKUS, Five Eyes and FPDA to name a few international treaties, agreements and arrangements. Therefore, DS argues that the DIP is short on funding for Strategic sea and airlift enablers – the Logistics for movement en-masse on a global not just penny packet regional scale!
DS would also argue that the DIP underfunds critical military ISTAR enablers and force multipliers – the upshot being too few AEW, LRMPA, AT and AAR to meet NATO tasking in a crisis or to guarantee defence of an OT such as the Falkland Islands.
The full CPUDS paper can be found here, below DS has produced a précis version.
Précis Version of the CPUDS DIP Paper
The 2026 UK Defence Investment Plan (DIP) is intended to convert the 2025 Strategic Defence Review (SDR) into a funded programme. This paper argues that delayed publication, shifting spending commitments and uncertainty over additional resources have already weakened its credibility. The Plan contains important commitments, but it does not yet reconcile ambition with funding, readiness, personnel, logistics and industrial capacity. Its central risk is the gap between a digitally integrated, technology-enabled vision and the practical challenge of delivering it while sustaining current capability.
The five essays assess the Royal Navy, British Army, Royal Air Force, cyber and information capabilities, and defence industry. Across them runs a common tension: the assumption that artificial intelligence, autonomy, digital networks and precision systems can compensate for limited conventional mass. The contributors support innovation but doubt that emerging systems are yet mature, affordable and resilient enough to replace proven capabilities. Technology cannot substitute for stockpiles, infrastructure, training, maintenance, secure supply chains or operational experience.
For the Royal Navy, the DIP is a financially driven bet on a “hybrid” fleet in which autonomous systems increasingly substitute for conventional surface and aviation assets. Investment in submarines, frigates, bases, munitions and the nuclear enterprise is welcome, but weaknesses remain in carrier aviation, amphibious capability, fleet support and overseas commitments. Because ships and specialist skills take years to regenerate, a failed transition would be difficult to reverse.
For the Army, the DIP supports reorganised divisions, recce-strike doctrine, digital integration and a mixed force of crewed and autonomous systems, alongside investment in armour, artillery, weapons, munitions and personnel. Yet the paper questions whether technology can replace physical mass or multiply “lethality” as claimed. Delivery will depend on procurement, recruitment, retention, training, logistics and reliable networks.
The RAF receives a comparatively coherent programme centred on Typhoon, F-35, the Global Combat Air Programme, collaborative combat aircraft, space and integrated air and missile defence. It is positioned as an integrator of air, space, digital command and autonomous systems. However, it must sustain current readiness while introducing complex capabilities and ensuring that skilled workforces, software, munitions, infrastructure and sustainment keep pace.
Cyber investment recognises the importance of defensive operations, electromagnetic activity and secure digital integration, but outcomes are difficult to assess. Success requires clear responsibilities, specialist skills, resilient networks and cooperation across government and industry. Defence industry likewise needs predictable demand, contracting certainty, workforce development and dependable funding.
Overall, the DIP offers a plausible direction but not yet a credible route to delivery. Its ambitions extend to 2035 and beyond while many enabling capabilities remain immature or under-resourced. Success depends on sustained political commitment, disciplined procurement, realistic priorities and protection of readiness and conventional capacity during transition. Without firmer resources and credible implementation, the DIP risks becoming another collection of aspirations vulnerable to delay, compromise and disappointment.
