Senior British figures at NATO have issued a stark warning to ministers, amid concerns the Government is “dithering” over defence spending at a pivotal moment for the alliance.
Officials fear that continued hesitation over funding commitments — and delays to rearmament plans — could weaken the UK’s standing inside NATO, both politically and militarily.
The Ministry of Defence has been cautioned that, without clear forward spending commitments, Britain risks slipping down NATO rankings — not only in defence expenditure as a share of GDP but also relative to other member states’ contributions, which could affect its influence within the alliance.
Concerns are understood to have been conveyed by Angus Lapsley, the UK’s permanent representative to NATO, Nick Catsaras, a NATO assistant secretary-general and Keith Blount, Admiral and outgoing Deputy Supreme Allied Commander Europe.
Senior figures are said to believe that delays risk undermining Britain’s credibility at a time when deterrence and alliance unity are under intense scrutiny.
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There is particular anxiety about how the United States might respond.
US President Donald Trump has repeatedly criticised NATO members he considers insufficiently contributing to collective defence.
Sources suggest that any public admonishment from the White House could quickly escalate diplomatically, with NATO Secretary General Mark Rutte potentially echoing those concerns to maintain alliance cohesion.
Such a scenario could damage Britain’s reputation as one of NATO’s leading military powers.
Ahead of a NATO summit last June, Prime Minister Keir Starmer committed to increasing defence spending to 2.5% of GDP by April next year, with a longer-term ambition of reaching 3% before the end of the next Parliament.
Weeks later, at a summit in The Hague, he joined 30 other NATO leaders in backing a more ambitious trajectory, supporting a target of 3.5% of GDP for core defence spending by 2035.
The Government’s delay in publishing the Defence Investment Plan (DIP) risks undermining the UK’s credibility, emphasising the need for timely action to uphold NATO commitments.
Senior defence sources fear that, without significantly increased funding, some of the proposed capabilities in the DIP may prove undeliverable.
Defence sources are concerned about the lack of munition stockpiles, the Royal Navy’s fleet readiness, air defence resilience, and personnel recruitment and retention, which are at 200-year lows.
Delays in publishing the plan are said to reflect unresolved Treasury negotiations over long-term funding guarantees.
Britain remains one of NATO’s largest defence spenders in absolute terms and a key contributor to alliance operations.
But in a climate of heightened geopolitical tension, perception matters, and if the UK’s perceived underperformance persists, it could undermine NATO’s collective security and future cooperation.
If the UK is perceived to fall short of its NATO commitments, especially after endorsing higher targets, it could face serious diplomatic repercussions, underscoring the need for careful consideration of the political implications.
The key challenge for ministers is balancing fiscal caution with NATO leadership, as delays could weaken Britain’s strategic influence at a pivotal moment, calling for decisive action.
The Daily Express reported that James MacCleary, defence spokesperson for the Liberal Democrats, said: “While ministers drag their feet on the DIP, British SMEs are being pushed to the brink and we are sleepwalking into even deeper dependence on the US for critical kit we should be building — and sustaining — at home.
Delays are endangering vital sovereign capabilities like helicopter manufacturing in Yeovil which we could lose altogether if this squabbling between government departments continues.”
Shadow Defence Secretary James Cartlidge said: “Labour’s DIP is long overdue, having been promised for autumn 2025, and there is one overriding reason why — this is a Government that has prioritised welfare over defence of the realm.”
