Day 18 | Proposal 17
17
National Security
Rebuilding Britain's defence capability for a more dangerous and uncertain world.
Current policy — Manifesto 1.1
Proposal 17 would progressively increase defence spending to 5% of GDP within five years, rebuilding capability across nuclear deterrence, conventional forces, cyber resilience and personnel.
Published Manifesto 1.1 policy. The sections below set out the proposal as published. Questions and challenges are open questions, not settled answers.
Key figures
- Peacetime defence spending target within five years
- 5% of GDP
- 8% is not the normal peacetime target — only a potential wartime mobilisation level if national circumstances ever required it.
1. What the manifesto commits to
Section VII, Policy 20 establishes a programme to rebuild Britain's defence capability.
The central peacetime commitment is to progressively increase defence spending to 5% of GDP within five years.
The earlier 8% figure is not the normal peacetime target. It should only be understood as a potential wartime mobilisation level if national circumstances ever required it.
2. Why defence is treated as a core function
National security depends on credible deterrence, deployable conventional forces, resilient infrastructure and people who are properly recruited, trained, housed and retained.
The proposal therefore treats defence as a broad national capability rather than simply a spending line.
3. Four priority areas
A credible defence policy must protect the country, sustain the people who serve and prepare Britain for threats that are changing rapidly.
- Nuclear deterrence: Continuous-at-sea deterrence, warhead infrastructure, submarines, and nuclear command and control.
- Conventional forces: Ships and aircraft, armoured vehicles, ammunition and missiles, and drones and logistics.
- Cyber: Offensive cyber capability, defensive cyber capability, and protection of critical infrastructure.
- Personnel: Recruitment and retention, housing, pay, training, and support for veterans.
4. A five-year defence trajectory
The working manifesto sets out an illustrative path for reaching the 5% peacetime commitment. The starting point is an original modelling assumption, not a newly verified current-spending figure.
This trajectory is illustrative rather than independently certified current fiscal modelling.
| Stage | Defence spending |
|---|---|
| Original assumed starting point | ~2.5% of GDP |
| Year 1 | 3.0% |
| Year 2 | 3.5% |
| Year 3 | 4.0% |
| Year 4 | 4.5% |
| Year 5 | 5.0% |
Illustrative only. The starting point is an original modelling assumption, not a newly verified current-spending figure.
5. Scale and fiscal significance
Reaching 5% of GDP would be a very substantial increase and one of the manifesto's largest fiscal commitments.
The trajectory is illustrative. Detailed implementation would need to test affordability, sequencing, industrial capacity and the outcomes delivered for each additional pound.
The objective is capability, readiness and resilience — not a headline percentage without measurable results.
6. The details still need testing
The working master identifies the spending destination, the five-year ambition and the broad capability priorities.
It does not yet provide a complete procurement programme, independently certified costing or detailed implementation architecture. Those elements should be developed through evidence and scrutiny.
7. Core commitment
Core commitment
Make defence a central function of government. Progressively increase spending to 5% of GDP within five years, focus investment on the nuclear deterrent, conventional forces, cyber capability and personnel, and retain 8% only as a potential wartime mobilisation level — not a normal peacetime target.
Questions for public scrutiny
Nothing in Manifesto 1.1 is presented as settled fact. These are open questions the proposal must be able to answer — they are not answered here.
- 01What fiscal pathway could reach 5% of GDP without weakening essential public services or economic stability?
- 02Which capability gaps should be addressed first, and which measurable outcomes should determine whether additional spending is working?
- 03How should Britain balance nuclear deterrence, conventional readiness, cyber resilience and support for personnel?
- 04What procurement reforms would reduce delay, waste, cost overruns and dependence on fragile supply chains?
- 05How should investment strengthen Britain's domestic defence industry, skills base and sovereign manufacturing capacity?
- 06What recruitment, retention, housing and pay reforms are needed to support serving personnel and veterans?
- 07Which safeguards should govern offensive cyber capability and the protection of civilian critical infrastructure?
- 08Under what clearly defined circumstances could a wartime mobilisation level above the 5% peacetime commitment be justified?
Source: Manifesto 1.1 Complete Working Master, Section VII, Policy 20 — Defence at 5% of GDP. This release is Day 18 / Proposal 17 in the campaign sequence. Journey days and public-release proposal numbers are not always the same.
Download the Manifesto 1.1 Complete Working Master (PDF)Read. Question. Challenge. Improve.
This is a public-scrutiny working proposal. Questions, evidence, objections and alternatives are welcome.
Have Your Say
What is your view on this proposal?
Scrutiny, not endorsement. Disagreement is as useful here as support.
Responses are counted anonymously and the running totals are shown publicly beside each option. One response per device, changeable at any time.
Have an objection, question or better alternative?
Set out your argument. Serious challenges shape later versions of the manifesto.