George Robertson, an ex-defence secretary from Starmer’s Labour party, was to use a speech to accuse ministers of “corrosive complacency”, according to excerpts reported by the Financial Times and BBC.

“We are underprepared. We are underinsured. We are under attack. We are not safe,” Robertson was to say, calling the Iran war a “rude wake-up call”.

Robertson, NATO secretary general between 1999 and 2004, was commissioned by Starmer’s government to lead a review of the UK’s defence capabilities, which was published last year.

A 10-year defence investment plan following the review was meant to be published late last year but has not yet been produced.

Robertson, 80, told the Financial Times there was a gap between Starmer’s rhetoric on defence and the action he had delivered, saying the prime minister was “not willing to make the necessary investment”.

In his speech in Salisbury, southern England on Tuesday night, Robertson was to accuse “non-military experts” in Britain’s treasury of “vandalism”, according to the reports.

“Lip service is paid to the risks, the threats, the bright red signals of danger — but even a promised national conversation about defence can’t be started,” he was to say.

Starmer has pledged to raise defence spending to 2.5 percent of gross domestic product from next year, increasing to three percent in the next parliament.

The rise comes amid demands from US President Donald Trump that Nato allies spend more on defence, and as Europe faces continued Russian aggression.

“We are delivering on the Strategic Defence Review to meet the threats we face,” a government spokesman said, adding the defence investment plan will be published “as soon as possible”.