Former NATO Secretary-General George Robertson said Tuesday that Britain is critically under-prepared for war and risks alienating its closest allies [1].

The warning comes as the UK government faces pressure to align its military investment with a rising tide of spending among NATO members. Failure to meet these benchmarks could strain the strategic relationship between the UK and the U.S., while diminishing the UK's influence within the alliance [1, 2].

Speaking at a Strategic Defence Review session in London on July 7, Robertson highlighted the absence of a commitment to spend 3.5% [1] of GDP on defence. He said the current investment plan is insufficient to meet modern security threats.

"We risk a frosty response from NATO allies if we do not commit to the 3.5% defence spending target," Robertson said [1].

Robertson was joined in his concerns by former British Army commander Richard Barrons [1, 2]. The leaders said that other member states, including Germany and Poland, are moving more aggressively to bolster their military capabilities [1]. This gap in investment suggests that Britain may no longer be keeping pace with the collective security requirements of the North Atlantic Treaty Organization [2].

"Britain is not safe and critically under-prepared for war," Robertson said [2].

The comments precede a NATO summit, where spending targets and collective defence strategies are expected to be central themes. The lack of a clear path toward the 3.5% [1] target may lead to diplomatic friction as allies evaluate the burden-sharing contributions of each member state [1].

Britain is not safe and critically under-prepared for war.

The push for a 3.5% GDP spending target reflects a shift in the global security landscape, where traditional allies are accelerating militarization to counter emerging threats. For the UK, failing to meet this benchmark is not merely a budgetary issue but a diplomatic liability that could reduce its leverage during NATO summits and complicate its security guarantees with the U.S.