Leaking details from a National Security Council (NSC) meeting is "utterly dysfunctional and destructive", Harriet Harman has said.

While there are often briefings out of cabinet and Parliamentary Labour Party meetings, revealing details of top-secret talks held by the NSC "should be a red line", the former deputy Labour leader said.

Her comments on Sky's Electoral Dysfunction podcast come after intimate details of NSC deliberations held just preceding and following the beginning of the US-Israeli war on Iran were revealed by The Spectator.

Iran war latest - follow live

The magazine reported that at a meeting last Friday, Sir Keir Starmer wanted to allow the US to use British bases for political reasons, but was blocked by four cabinet ministers, led by Energy Secretary Ed Miliband.

The prime minister then agreed to it for defensive purposes on Sunday after the US made a formal request the previous day.

Although Sir Keir has said there was not a "specific decision to be made" on the Friday, the government has not denied the story, so this appears to be the first leak of top-secret NSC deliberations since 2019.

? Listen to Electoral Dysfunction on your podcast app ?

Speaking to our political editor Beth Rigby on the Electoral Dysfunction podcast, Baroness Harman hit out at the leaker or leakers, saying national security discussions need to be held in private.

She said: "The prime minister has got to be able to go to his NSC and discuss issues with colleagues - that's how government functions."

'Red line' has been crossed

Details of cabinet meetings and weekly meetings of Labour MPs often leak, and although Harman "disapproves" of that, "it's not the end of the world".

"But there should be a real red line against briefing out of National Security Council," she continued.

"It's particularly worrying because it seems the briefing is not criticising the decision. They're supporting the decision, but they're just saying it wasn't Keir Starmer's original decision - he was just overridden by other members of the cabinet.

"So I think it's utterly dysfunctional and destructive, and I thoroughly disapprove of it. I'm really dismayed about it.

"Any prime minister needs to be able to discuss with the cabinet colleagues in the NSC and actually not be undermined."

Former Scottish Conservative leader Ruth Davidson agreed, saying the NSC should be "a sacrosanct space where the most top-level security people" are "able to discuss things and make decisions in the national interest".

Read more from Sky News:
Trump sacks Kristi Noem
UK diesel hits 16-month high

Leaks from the NSC are rare, and the last time conversations appeared in the media was in 2019, when contents of two meetings were published in newspapers.

In September that year, details of an NSC meeting about bringing back the British children of Islamic State fighters in camps in northern Syria were published by the Mail On Sunday.

Before that, in April, details of an NSC meeting about whether Chinese firm Huawei should be involved in the UK's 5G network were published in The Daily Telegraph.

Then prime minister Theresa May launched an internal leak inquiry, which led to the firing of the then defence secretary, Sir Gavin Williamson, although he denied being responsible.

Downing Street has not said if Sir Keir has launched an inquiry after the leak of last week's NSC meetings.

(c) Sky News 2026: Leak from UK security meeting on Trump's war request branded 'utterly destructive'