Iran threatens to leave global anti-nuclear treaty over ‘snapback’ sanctions

However, its status as a signatory may now be in jeopardy after the E3 nations confirmed yesterday that they would trigger the “snapback” process to reimpose UN Security Council sanctions on the Islamic Republic.

If it does pull out, it would join India, Pakistan and Israel in the group of high-profile non-signatories who are believed to have nuclear capabilities.

Commenting on the prospective withdrawal, Iranian MP Hossein-Ali Haji-Deligani said: "These are the consequences of activating the snapback mechanism."

The measures - including asset freezes, visa bans, an arms embargo and restrictions on ballistic missile production and nuclear enrichment - were lifted as part of the 2015 Joint Comprehensive Plan of Action (JCPOA), more commonly known as the Iran nuclear deal.

But a clause in that agreement gave Western signatories the power to reactivate UN-backed sanctions if the Islamic Republic breached its terms.

Tehran has long since shattered the limits on its enrichment of uranium, with the US and Israel both arguing that the regime was close to obtaining a nuclear weapon.

Given the breakdown of talks between Washington and Tehran on a fresh agreement, the E3 group confirmed yesterday that it would start the 30-day clock to reactivate the sanctions.

UK Foreign Secretary David Lammy highlighted the “threat to global peace and security” posed by Iran’s nuclear programme.

"Despite repeated warnings, Iran has made no substantive effort to meet the conditions of our extension offer and has consistently failed to provide credible assurances on the nature of its nuclear programme,” he said.

The snapback mechanism is not subject to the veto power of permanent members of the UN Security Council (including Iranian allies Russia and China) so the sanctions will come into force next month unless a new resolution to prevent it is approved by a majority of the council.

For his part, Iranian Foreign Minister Abbas Araghchi responded by saying his country would be open to "fair and balanced negotiations" as long as other countries "show seriousness and goodwill and avoid actions that harm the chances of success", referring to recent US strikes on Iranian nuclear sites.

However, he has previously stated that there can be no prospect of Iran completely abandoning its nuclear programme – which it maintains is intended for energy production – or ceasing the enrichment of uranium.

This creates an impasse with the Trump administration (the president is a longtime critic of the JCPOA), which insists that Iran must agree to end its enrichment in order to prevent further military action.