Downing Street advisers are examining whether the government could bring forward its ambition to spend 3% of GDP on defence to within this Parliament, potentially by 2029. The work follows the Prime Minister’s weekend intervention at the Munich Security Conference and is being handled alongside the finalisation of a delayed Defence Investment Plan. Officials stressed decisions are not yet taken and described current reporting as speculative. (nz.news.yahoo.com)
The formal commitment on the statute books remains to reach 2.5% of GDP on NATO‑qualifying defence from April 2027, with an ambition to move to 3% in the next Parliament. Ministers say the 2.5% step is fully funded, largely via a reduction in Official Development Assistance to 0.3% of GNI from 2027. A House of Commons Library explainer confirms the timeline and funding route. (gov.uk)
Costings sharpen the choice set. The Office for Budget Responsibility assessed in March 2025 that reaching 3% by 2029–30 would require around £17.3bn in additional annual spending in that year. Reporting citing the Institute for Fiscal Studies’ Bee Boileau suggests the net figure could be lower-about £13–14bn-once already‑planned uplifts are netted off, but that would still require difficult trade‑offs. (commonslibrary.parliament.uk)
The strategic backdrop has shifted. NATO updated its guidance in June 2025, with Allies committing to invest 5% of GDP on security and defence by 2035. Of that, at least 3.5% is to be core defence under NATO’s standard definition, with up to 1.5% covering resilience, industrial base and critical infrastructure. This represents a material step up from the long‑standing 2% benchmark. (nato.int)
UK outturns sit above the older NATO minimum but below the new trajectory. NATO‑qualifying UK defence spend was estimated at 2.3% of GDP in 2024-about £64.6bn. The 2025 and 2027 steps are intended to lift that ratio, but closing the distance to 3% within this Parliament would still represent a multi‑billion‑pound acceleration. (commonslibrary.parliament.uk)
Affordability pressures inside the programme are acute. According to multiple reports, the Ministry of Defence faces a funding shortfall of roughly £28bn over the next four years against existing plans-one factor behind delays to the Defence Investment Plan. In January, Chief of the Defence Staff Air Chief Marshal Sir Richard Knighton told MPs the services could not deliver all programmes at the desired pace within the allocated budget. (civilserviceworld.com)
Funding options under discussion reflect those constraints. Whitehall sources have pointed to further ODA reductions, reprofiling climate‑and‑energy transition allocations, or re‑prioritising major capital schemes such as high‑speed rail as potential offsets; borrowing remains politically sensitive given fiscal rules. The Treasury has not recognised claims it is resisting a specific ‘3% plan’ and says discussions are cross‑government and led by the Prime Minister. (nz.news.yahoo.com)
Those fiscal rules matter. The OBR’s November 2025 forecast shows the government meeting its targets for a current budget surplus and for public sector net financial liabilities to be falling in 2029–30, but with finite headroom-around £22bn on the current budget measure. Any earlier move to 3% would have to fit within, or be accompanied by changes to, this framework. (obr.uk)
The Prime Minister’s signal at Munich was deliberate. He argued that Europe must “spend more, deliver more, and coordinate more” and said the UK seeks to move from over‑dependence on the US to interdependence with European partners. The remarks track NATO’s new 2035 baseline and were read in allied capitals as a nudge towards an earlier UK timetable. (gov.uk)
Washington would welcome acceleration. US officials have privately pressed for faster European movement, and sources suggest an in‑Parliament shift to 3% would be viewed positively. That aligns with the Alliance’s 3.5% core defence objective, but also raises near‑term procurement and workforce pressures for the UK defence industry. (nz.news.yahoo.com)
Domestically, political management is in flux. Morgan McSweeney resigned as Downing Street chief of staff on 8 February 2026; several insiders credit him with pushing for higher defence outlays. His exit has reportedly stiffened Treasury caution, though ministers dispute any change in stance. (theguardian.com)
Ministers maintain they are already delivering the largest sustained increase in defence investment since the Cold War, citing an extra £5bn this year and the step to 2.5% by 2027. Foreign Secretary Yvette Cooper has nonetheless said the UK will “need to go further”. The Defence Investment Plan, expected between March and May 2026, is now the key document to watch for sequencing and any decision on an earlier 3% path. (hansard.parliament.uk)