There is a critical question hanging over the events of the past few days.

Behind the chest-thumping from Donald Trump, and the bewilderment beyond at his statecraft-by-social-media, doubts have now reached fever pitch about the success of the American bombing of Iran’s nuclear sites.

Leaks from the US Defence Department suggest the bunker busting bombs dropped on Iran’s three nuclear enrichment sites might only have set the country’s nuclear capabilities back by months.

“We were assuming that the damage was going to be much more significant than this assessment is finding,” said one of three sources, speaking to NBC News.

“This assessment is already finding that these core pieces are still intact. That’s a bad sign for the overall programme.”

NBC News has spoken to three sources – all of whom say that the initial assessment by the Defence Intelligence Agency has concluded that the US airstrikes were not as effective as Mr Trump claimed.

Similar leaks were made to The New York Times, The Washington Post and CNN.

Follow latest developments in our live blog

Responding to the CNN leak, White House press secretary Karoline Leavitt said: “This alleged assessment is flat-out wrong and was classified as ‘top secret’ but was still leaked to CNN by an anonymous, low-level loser in the intelligence community.”

She continued: “The leaking of this alleged assessment is a clear attempt to demean President Trump, and discredit the brave fighter pilots who conducted a perfectly executed mission to obliterate Iran’s nuclear programme. Everyone knows what happens when you drop 14 30,000lb bombs perfectly on their targets: total obliteration.”

In his address to the nation on Saturday night, Mr Trump had said: “I can report to the world that the strikes were a spectacular military success. Iran’s key nuclear enrichment facilities have been completely and totally obliterated.”

US Defence Secretary Pete Hegseth has also dismissed the leaks, saying: “Based on everything we have seen – and I’ve seen it all – our bombing campaign obliterated Iran’s ability to create nuclear weapons.

“Our massive bombs hit exactly the right spot at each target – and worked perfectly.”

“The impact of those bombs is buried under a mountain of rubble in Iran, so anyone who says the bombs were not devastating is just trying to undermine the president and the successful mission.”

Battle Damage Assessments (BDAs) take a long time to be close to conclusive and require extensive intelligence analysis.

Speaking to Sky News, former director of the CIA and top US General David Petraeus cautioned about drawing any conclusions at this stage.

“Well, the truth is, it is just too soon. And those who are leaking should know that it takes a long time to do the battle damage assessment. And those who have actually pushed back in very conclusive ways also probably should have wait for the full results,” Gen Petraeus said.

“This is a very painstaking process. It’s an effort by the overall intelligence community, not just Defence Intelligence Agency. In fact, the CIA would be the lead in this effort to mine all sources of intelligence, imagery, intelligence of all types, signals, cyber, even open-source intelligence.”

Read more analysis:
There’s one F word Trump fears most
Can Tehran regard Trump as trusted broker of peace?

Beyond the debate over the extent of the damage, questions remain over whether Iran might have managed to move equipment including centrifuges. Critically too, the whereabouts of about 400kg of highly enriched uranium is unknown.

The classified assessment of the military’s operation in Iran has been transmitted to Congress and has been viewed by some senators in a secure location, according to two sources with direct knowledge of the situation.

“I’ve reviewed the classified material,” Democratic Party Senator Tim Kaine, a member of the Armed Services Committee, said.

“I’m a little bit disappointed that my colleagues went and looked at it and mainly started talking about it publicly. That’s not we’re supposed to do with a classified report,” he added.

Speaking on Sunday to NBC’s Meet The Press, Israel’s ambassador to the UN Danny Danon insisted Iran’s nuclear capability had been dramatically set back.

“I think it’s still very early to jump into conclusions. We have to wait for the assessment. I can tell you one thing for sure. If you look where Iran was 12 days ago and where they are today, you understand that both Israel and the US were able to degrade the capabilities, push them back decades, and if we had an imminent threat, it doesn’t exist anymore.”

The UK will buy at least 12 F-35 stealth jets that can carry nuclear warheads in the most significant strengthening of its nuclear capability in a generation, the government has said.

Today, Sir Keir Starmer will tell a summit of NATO allies in The Hague that the new squadron will join an alliance mission that can be armed with US nuclear weapons.

The dramatic move will doubtless draw condemnation and concern from Russia and China.

But it comes at a time of growing global insecurity – and as the prime minister and his European and Canadian counterparts scramble to convince Donald Trump they are serious about bolstering their ability to defend Europe, instead of overly relying on the United States.

The US president, a long-standing NATO sceptic, raised questions about whether he would uphold the alliance’s founding Article 5 principle – that an attack on one is an attack on all – before he even arrived in the Dutch city last night.

An urgent need to keep Mr Trump on side has prompted NATO allies to agree to increase spending on defence and national resilience to a new target of 5% of GDP by 2035.

As part of this push to rearm, Sir Keir will give the Royal Air Force the ability to carry airborne nuclear warheads for the first time since the 1990s.

“In an era of radical uncertainty we can no longer take peace for granted,” he said.

“These F-35 dual capable aircraft will herald a new era for our world-leading Royal Air Force and deter hostile threats that threaten the UK and our allies.

“The UK’s commitment to NATO is unquestionable, as is the alliance’s contribution to keeping the UK safe and secure, but we must all step up to protect the Euro-Atlantic area for generations to come.”

It was not immediately clear when the F-35 jets would be bought or how much they will cost, but the new squadron will be part of a NATO-led nuclear deterrence mission.

That is in contrast to the UK’s national nuclear deterrence, based on a fleet of four nuclear-armed submarines, though they too are used to defend the whole of the alliance.

Mark Rutte, the head of NATO, applauded the plan – saying: “The UK has declared its nuclear deterrent to NATO for many decades, ​and I strongly welcome today’s announcement that the UK will now also join NATO’s nuclear mission and procure the F-35A.

“This is yet another robust British contribution to NATO.”

Aircraft operated by a small number of NATO countries, including Belgium, Germany and the Netherlands, are cleared to carry US-provided nuclear weapons in a war.

The RAF and the Royal Navy already operate F-35B jets that can fly off Britain’s two aircraft carriers, but they are not equipped to drop nuclear warheads.

The new planes will be the F-35A variant, operated by the air force, that take off from land but can fly further and be armed with nuclear or conventional weapons.

The government said they would all be based together at RAF Marham in Norfolk.

The government has long planned to purchase a total of 138 F-35 aircraft, but has so far only acquired around three dozen – seven years since the first jets entered service.

The decision to purchase 12 of the A-variant does not mean extra aircraft.

It just means a diversification in the fleet – something the RAF has long been pushing for – though it’s a decision some in the Royal Navy have long pushed back against, believing it would reduce even further the number of the B-version that operate from their carriers.

Read more:
PM warns of ‘era of radical uncertainty’
Podcast – What is NATO without America?

The government described the plan to purchase nuclear-capable aircraft as the “biggest strengthening of the UK’s nuclear posture in a generation”.

Defence Secretary John Healey said a major defence review published earlier in the month highlighted new nuclear risks.

“It recommended a new UK role in our collective defence and deterrence through a NATO-first approach,” he said.

However, the public version of the Strategic Defence Review stopped short of making any specific recommendation.

It merely said “the UK must explore how to support the US and its NATO allies in strengthening extended deterrence across the Euro-Atlantic”.

The F-35 aircraft is made by the US defence giant Lockheed Martin, but the British defence company BAE Systems is also a key contributor.

The order will support 20,000 jobs in the F-35 programme in the UK.