This week, the International Atomic Energy Agency, the UN’s atomic watchdog, claimed that Iran is deliberately seeking to conceal its activities at three suspected nuclear sites. These allegations have once more drawn to one of the fundamental shortcomings of the 2015 nuclear deal: that it has failed to force Tehran to make a comprehensive declaration about every aspect of its nuclear activities. As part of the IAEA’s quarterly update, the organisation has produced two reports on Iran’s nuclear activities, raising fresh concerns about its undisclosed nuclear activities. One report, the first compiled since the signing of the nuclear deal, provides an alarming update on the current level of Iran’s stockpiles of enriched uranium, which it concludes have tripled during the past three months, after Tehran announced it was to resume its enrichment programme in response to Washington’s punitive sanctions regime. This means that Tehran now possesses five times the amount of enriched uranium that it is allowed under the terms of the 2015 deal. Meanwhile, a separate report has revealed that IAEA inspectors identified three possible undeclared locations where nuclear material may have been stored in secret. Among the sites listed is a facility in the Turquzabad district of Tehran, which western intelligence officials claim is being used as an “atomic archive” for information on Iran’s former nuclear weapons programme. According to a CIA assessment published towards the end of the Bush Jr administration, Iran was working on developing nuclear weapons until 2003 when the regime, fearing that the US-led coalition would attack Iran following the overthrow of Iraqi dictator Saddam Hussein, halted the programme and placed the relevant technology into cold storage. Iran has consistently denied having a nuclear weapons programme but western intelligence officials believe the regime has continued working on various aspects of the programme, such as missile delivery systems and processing nuclear materials like uranium to weapons grade. The latest IAEA reports appear to confirm the view that Iran has resumed work both on building up its stockpiles of enriched uranium – a key component in the construction of nuclear warheads – as well using secret storage facilities for material used in the nuclear programme. Iran has so far failed to respond to numerous requests by the IAEA for clarification on its latest findings, including soil samples taken from Turquzabad, which IAEA officials say contain traces of uranium that Tehran has failed to explain. Iran’s failure to co-operate with the IAEA is entirely in keeping with its approach to the nuclear issue. For it has been a perennial feature of the nation’s nuclear programme, dating back to the early 1990s, when it first began working on the scheme, that Tehran has consistently refused to comply with its international obligations to disclose details about its nuclear activities. As a long-standing signatory to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), which the country first signed in 1968 when it was still ruled by the Shah, Iran has an obligation to provide details of any new nuclear-related facilities under development. And yet, since Iran first began work on developing the capabilities to build nuclear weapons, it has consistently sought to keep key facilities secret from the outside world. For instance, the existence of the massive underground uranium enrichment facility at Natanz was only revealed after opposition groups succeeded in identifying the site and sounding the alarm in 2002. Prior to the signing of the 2015 deal, tensions between Iran and the West over its nuclear activities were primarily caused by the regime’s persistent attempts to mislead IAEA inspectors during officially-sanctioned visits. In one instance the Iranians razed to the ground a secret nuclear facility at Lavizan Shiyan after it had been identified by US satellites. The regime even went as far as removing all the topsoil from around the site to cover its tracks. The latest IAEA claims raise some awkward questions for the three European powers – Britain, Germany and France – that continue to support the 2015 nuclear deal. The Europeans have consistently argued that the best way to prevent Iran from developing nuclear weapons is to stick with the nuclear deal. But the evidence provided by the IAEA this week suggests that, on the contrary, the Iranians no longer have any genuine interest in complying with their side of the agreement. <em>Con Coughlin is the Telegraph’s Defence and Foreign Affairs Editor and the author of Khomeini’s Ghost</em>