The White House has signalled its intention to reopen negotiations on the Joint Comprehensive Plan of Action, the multilateral agreement governing Iran’s nuclear programme, prompting an immediate rebuke from Downing Street. A senior administration official confirmed late Tuesday that President Donald Trump is pursuing a revised framework that would impose stricter limits on Tehran’s enrichment capacity and extend sunset clauses beyond 2030.
The move, described by the official as a “reset of a flawed deal”, has been met with unease in European capitals. Prime Minister’s spokesman told journalists that Britain expects full consultation with Washington before any unilateral changes are tabled. “The JCPOA was the product of years of diplomacy and enjoys the support of all signatories,” the spokesman said. “Any attempt to unilaterally rewrite its terms would undermine the trust that underpins transatlantic security.”
The original agreement, signed in 2015 by Iran, the United States, the United Kingdom, France, Germany, Russia, China and the European Union, limited Iran’s uranium enrichment in exchange for sanctions relief. Mr Trump withdrew the US from the accord in 2018, citing insufficient restrictions, and reimposed sweeping sanctions. Iran subsequently breached key thresholds, enriching uranium to 60% purity, close to weapons-grade.
Diplomatic sources in Vienna, where the International Atomic Energy Agency monitors compliance, said the latest American proposal includes demands for snapback mechanisms, inspections of military sites and a commitment from Iran to halt ballistic missile development. Tehran has consistently rejected such conditions.
The timing is delicate. The IAEA’s quarterly report, due next week, is expected to confirm that Iran’s stockpile of enriched uranium now exceeds 30 times the limit set under the original deal. European negotiators have for months attempted to revive the 2015 accord through indirect talks in Vienna, but those efforts have stalled since the collapse of the US-Iran prisoner swap negotiations last autumn.
Dr Patricia Kazemi, a senior fellow at the Royal Institute of International Affairs at Chatham House, described the American approach as “strategically risky”. She said: “By reopening the deal without a clear diplomatic pathway, Washington risks alienating its European allies and pushing Iran further toward weaponisation. The British demand for consultation is not merely procedural; it reflects a genuine concern that the administration is acting unilaterally in a matter with global security implications.”
The Prime Minister’s spokesman added that Britain remains committed to the original JCPOA and will continue to engage with all parties, including the United States, to ensure the agreement is upheld. “We are urging restraint and dialogue,” the spokesman said. “Consultation is not a luxury. It is a necessity.”
The development comes as the Prime Minister prepares for a phone call with President Trump scheduled for Thursday. Officials in London said the conversation will cover trade, defence spending and the Middle East, but that the Iran deal is likely to dominate. Downing Street has not ruled out issuing a joint statement with France and Germany, known as the E3, to reaffirm their collective support for the existing accord.
In Tehran, Foreign Ministry spokesman Nasser Kanaani dismissed the American proposal as “neither new nor constructive”. He said Iran would only negotiate within the framework of the original agreement and warned that any further pressure would be met with “a firm response”. The IAEA has reported that Iran continues to install advanced centrifuges at its Natanz and Fordow facilities, though it has not yet resumed enrichment to 60% since a pause in June.
The situation underscores the fragility of the transatlantic partnership on one of the most consequential foreign policy issues of the decade. For Britain, the imperative is clear: maintain unity with European allies while preventing the collapse of a deal that, however imperfect, has kept Iran’s nuclear programme under some form of international supervision. For the Trump administration, the calculus appears to be driven by domestic considerations ahead of the presidential election, with the promise of a tougher stance on Iran playing well with key constituencies.
As the stand-off intensifies, the Prime Minister faces a delicate balancing act: affirming Britain’s alliance with Washington while defending the multilateral order that has long been a cornerstone of British foreign policy. The coming weeks will test whether that order can withstand the centrifugal forces of unilateralism.
