UK rearmament and warfighting readiness

Claire Mills; Louisa Brooke-Holland; Timothy Robinson

On 30 June 2026, the government published its long-awaited Defence Investment Plan (DIP). The government had pledged to publish the DIP before the NATO summit, which begins in Turkey on 7 July 2026.

The DIP has a 10-year focus but specifically sets out the Ministry of Defence’s spending and equipment priorities for the next four years, to financial year 2029/30. Before publishing the plan, the Ministry of Defence (MOD) said that it had been “refocused” towards more immediate priorities, including “getting the latest kit into the hands of military personnel on the frontline”. Concerns over an earlier version of the Defence Investment Plan, and the financial settlement underpinning it, prompted the resignation of Defence Secretary John Healey and Armed Forces Minister Al Carns in early June 2026.

Strengthening warfighting readiness and embracing autonomous and AI technologies underpins much of the plan. However, it also makes significant decisions on the future of existing programmes and capabilities, such as the next-generation fighter aircraft, the Ajax armoured vehicle and the capabilities that will comprise a future hybrid navy.

The MOD has committed to provide an annual update to Parliament on delivery against the DIP. The first annual report will be published in July 2027.

This briefing provides links to Commons research briefings, Committee reports, parliamentary material, UK Government press releases and further reading related to UK rearmament and war fighting readiness.

Commons Library research briefings

Defence Investment Plan: Key decisions, 2 July 2026

UK aid: Reducing spending to 0.3% of GNI by 2027/28, 1 July 2026

Estimates Day debate: Spending of the Cabinet Office on security and resilience, 26 June 2026

Conscription and national service in the UK, 24 March 2026

Estimates Day debate: Spending of the Ministry of Defence, 3 March 2026

Strategic Defence Review 2025: Key points and paper series (A high-level overview of the Strategic Defence Review and relevant Commons Library research briefings)

UK defence spending, 10 October 2025

UK defence personnel statistics, 30 June 2025

Committee reports

Defence Committee’s response to the publication of the Defence Investment Plan, 30 June 2026

Evidence to the International Relations and Defence Committee for the inquiry on SDR implementation, 17 June 2026, from (PDF):

Rupert Pearce (UK National Armaments Director, Ministry of Defence)
Lt Gen Anna-Lee Reilly (Director-General, Core Delivery, Defence Equipment and Support, Ministry of Defence)
Avril Jolliffe (Director-General (International), Ministry of Defence)
Jim Carter (Director-General, Commercial and Industry, National Armaments Director Group, Ministry of Defence)

Evidence to the International Relations and Defence Committee for the inquiry on SDR implementation, 16 June 2026, from (PDF):

Air Chief Marshal Sir Richard Knighton (Chief of the Defence Staff, UK Armed Forces)

The UK contribution to European Security (PDF), Sixth Report of Session 2024–26, Defence Committee, HC 520, 19 November 2025 and the Government’s response, 20 January 2026

Ready for War? (PDF), First Report of Session 2023–24, Defence Committee, HC 26, 4 February 2024 and the Government’s response, 25 April 2024