Boost Defence Spending to 2.5% of GDP
Conservative · what the evidence says
An independent, source-checked look at Conservative’s policy “Boost Defence Spending to 2.5% of GDP” — what it would actually do across the things that affect your life. Every claim below quotes the source behind it. How this works.
Public finances & the next generation — Mixed picture
moderate · moderate confidence
The policy promises a fully funded path to 2.5% of GDP on defence by 2030, but independent analysts question whether the funding is genuinely new money, and the squeeze on other departments could shift fiscal pressure rather than resolve it. Whether this improves or worsens long-run sustainability hinges entirely on how the extra spending is actually funded.
The evidence
- The policy commits to boosting defence spending to 2.5% of GDP by 2030, supported by a fully funded plan. — conservatives.com (manifesto) — “boosting defence spending to 2.5% of GDP by 2030, supported by a fully funded plan”
- The plan aimed to be fully funded without increasing borrowing or debt. — gov.uk (media) — “This plan aimed to be fully funded without increasing borrowing or debt”
- The UK already spent an estimated 2.3% of national income on defence in 2024–25, so the incremental step is relatively small. — ifs.org.uk (institutional) — “the UK spent an estimated 2.3% of national income on defence in 2024–25”
- The commitment represents an extra £75 billion cumulatively over six years and a projected £87 billion on defence in 2030-31, an increase of £23 billion on 2024-25 spending. — gov.uk (media) — “representing an extra £75 billion cumulatively over six years and a projected £87 billion on defence in 2030-31, an increase of £23 billion on 2024-25 spending”
- The IFS questioned whether the headline 'extra' spending figures were misleadingly large, arguing they only made sense if the defence budget was assumed to have otherwise frozen in cash terms. — commonslibrary.parliament.uk (government) — “the Institute for Fiscal Studies (IFS), have questioned the government's calculation of the "extra" defence spending, suggesting figures like £13.4 billion were misleadingly large and only made sense if the defence budge…”
- The IFS emphasises that if higher defence spending is a structural and permanent need, it cannot be sustainably borrowed for, implying the need for higher taxes or cuts to other public services. — ifs.org.uk (institutional) — “if higher defence spending is a structural and permanent need, it cannot be sustainably borrowed for, implying the need for higher taxes or cuts to other public services”
- Substantial increases in defence spending, especially when coupled with ongoing health commitments, will put significant pressure on other unprotected government departments. — ifs.org.uk (institutional) — “substantial increases in defence spending, especially when coupled with ongoing commitments to health spending, will put significant pressure on other "unprotected" government departments”
- If defence reaches 2.5% by 2027 and health spending grows at its long-run average, other departments could face cuts of £8.6 billion a year. — resolutionfoundation.org (institutional) — “if defence spending reaches 2.5% by 2027 and health spending grows at its long-run average, other departments could face cuts of £8.6 billion a year”
Biggest unknown: Whether the 'fully funded plan' represents real additional fiscal headroom or simply reallocates pressure onto unprotected departments, higher taxes, or future borrowing.
Our reading: The policy states it is fully funded without increasing borrowing, which if true would leave the debt path unaffected — a neutral-to-marginal positive for O12 compared with an unfunded alternative. However, the IFS directly challenges the credibility of the 'extra spending' figures, arguing the baseline assumption inflates the claimed increment. More fundamentally, the IFS stresses that a structural permanent increase in defence spending cannot be sustainably borrowed for and must be met by tax rises or cuts elsewhere. The Resolution Foundation corroborates this: unprotected departments face an £8.6 billion annual squeeze if health and defence are both prioritised. This means the fiscal risk is real — if the funding plan does not materialise as claimed, the incremental defence spending adds to borrowing or compresses productive public investment (education, infrastructure, social care), both of which worsen long-run fiscal sustainability. On the other side, the policy does not propose unfunded tax cuts or explicit new borrowing; the stated commitment to full funding is a genuine fiscal constraint that, if delivered, avoids worsening the debt path. The tension is therefore between the stated funding commitment (a stabilising signal) and the credible independent concern that the arithmetic is not as clean as claimed and the opportunity cost lands on unprotected services. This genuine two-sided uncertainty — neither side without evidence — justifies 'mixed' rather than a clean 'worsens'. The magnitude is moderate because the sums involved (£23 billion/year by 2030-31) are large enough to matter materially to the debt path and departmental budgets, but the direction of the net effect genuinely depends on how funding is realised.
Crime, justice & national security — Helps
moderate · moderate confidence
Raising defence spending to 2.5% of GDP would strengthen the UK's military capabilities and NATO position, improving national security. The main caveat is that the marginal uplift from an already-high baseline is modest, and deterrence gains depend heavily on how the money is spent.
The evidence
- The policy commits to boosting defence spending to 2.5% of GDP by 2030, with a fully funded plan, to protect British interests and strengthen the UK's NATO position. — conservatives.com (manifesto) — “boosting defence spending to 2.5% of GDP by 2030, supported by a fully funded plan, to protect British interests and strengthen the UK's position in NATO”
- The UK was already spending an estimated 2.3% of national income on defence in 2024-25. — ifs.org.uk (institutional) — “the UK spent an estimated 2.3% of national income on defence in 2024–25”
- NATO estimates show the UK is expected to spend 2.4% of GDP on defence in 2025, already exceeding NATO's 2% target. — commonslibrary.parliament.uk (government) — “NATO estimates show the UK is expected to spend 2.4% of GDP on defence in 2025”
- The policy represents projected spending of £87 billion on defence in 2030-31, an increase of £23 billion on 2024-25 spending. — gov.uk (media) — “a projected £87 billion on defence in 2030-31, an increase of £23 billion on 2024-25 spending”
- Increasing to 2.5% would move the UK from 9th to 6th largest NATO defence spender as a share of GDP. — flint-global.com (media) — “Increasing to 2.5% would move the UK from being the 9th biggest NATO defence spender (in terms of percentage of GDP) to 6th on the current list”
- Additional funds are expected to target modernisation in ammunition stocks, AI, autonomous vehicles and digital warfare capabilities. — flint-global.com (media) — “The additional funds are expected to target modernization in key areas such as ammunition stocks, artificial intelligence, autonomous vehicles, and digital warfare capabilities”
- Boosting spending to 2.5% would reinforce the UK's commitment to NATO and its position within the alliance. — flint-global.com (media) — “Boosting defence spending to 2.5% of GDP would reinforce the UK's commitment to NATO and its position within the alliance”
Biggest unknown: Whether the additional funds are directed toward high-impact modernisation (AI, autonomous systems, ammunition) or absorbed by recruitment and conventional procurement with limited deterrence effect.
Our reading: The UK's national security posture is the core indicator for O5 in the defence dimension. The policy commits a material uplift — a projected £23 billion more per year by 2030-31 than 2024-25 — directed explicitly at deterring threats and strengthening NATO standing. The starting point is already above NATO's 2% floor (2.3-2.4% of GDP), so the marginal gap to 2.5% is relatively narrow; nonetheless, the uplift would move the UK meaningfully up the NATO ranking and fund targeted modernisation in areas (AI, autonomous systems, ammunition) directly relevant to contemporary deterrence. The direction is 'improves' because more resources for capability modernisation and NATO credibility is a plausible and evidence-supported mechanism. The magnitude is 'moderate' rather than 'major' because the marginal increment from an already-high baseline is limited, and the deterrence payoff is contingent on spending composition. Absent this policy, defence spending would remain at current levels (2.3-2.4% GDP), so the additional commitment represents a genuine, if not transformative, improvement to security posture. The time horizon is long-term: the target date is 2030 and capability investments take years to translate into operational effect. Confidence is moderate: the direction evidence is consistent, but the deterrence payoff depends on allocation choices not fully specified in the policy text.