UK and EU reimpose Iranian sanctions following UN snapback

Background to UN snapback and trigger for this

The Joint Comprehensive Plan of Action (JCPOA), agreed in 2015 between Iran and the E3/EU+3 (China, France, Germany, Russia, the United Kingdom, the United States, and the European Union), was designed to ensure the exclusively peaceful nature of Iran’s nuclear programme, in exchange for extensive sanctions relief. Under the JCPOA, Iran committed to strict limitations on its nuclear activities, and in return, the United Nations, EU, and US lifted a broad range of economic and financial sanctions, enabling renewed international trade and investment with Iran.

However, the diplomatic landscape shifted in 2018 when the US unilaterally withdrew from the JCPOA and reimposed those of its sanctions that it had lifted. In the years that followed, Iran incrementally ceased performing its JCPOA commitments, including exceeding uranium enrichment limits and restricting International Atomic Energy Agency (IAEA) access.

Despite ongoing diplomatic efforts, by August 2025, the E3 (UK, France, and Germany) concluded that Iran’s non-compliance could not be resolved through negotiation. On 28 August 2025, the E3 formally notified the UN Security Council of Iran’s significant non-performance, thereby triggering the “snapback” mechanism under the JCPOA. This mechanism provided for the automatic reimposition of UN sanctions that had been lifted under the agreement, unless the Security Council decided otherwise within 30 days - a decision that did not materialise.

As a result, from 28 September 2025, the UN sanctions on Iran that had been lifted under the JCPOA were formally reinstated.

UN sanctions

The snapback reinstates a suite of measures previously imposed by a series of UN Security Council resolutions between 2006 and 2015 (Resolutions 1696, 1737, 1747, 1803, 1835, and 1929). The reimposed UN sanctions include:

• A comprehensive arms embargo on Iran, prohibiting the supply, sale, or transfer of arms and related materiel to and from Iran.
• Prohibitions on the supply of nuclear-related technologies and materials, including dual-use items and technology that could contribute to Iran’s enrichment, reprocessing, or heavy-water-related activities, or to the development of nuclear weapon delivery systems.
• Asset freezes and travel bans on designated Iranian individuals and entities, particularly those linked to Iran’s nuclear and ballistic missile programmes. In line with this prohibitions on the provision of certain services, such as financial messaging, to designated persons and entities were reimposed.
• Restrictions on banking activities and investment related to Iran’s proliferation-sensitive sectors, including the freezing of assets of certain Iranian banks and entities.

UN member states are required to implement the reimposed measures in their domestic law. The practical impact of snapback will depend on whether, and to what extent, individual UN member states do this.

EU sanctions position

Following the reimposition of UN sanctions, the EU moved swiftly to reinstate a broad range of autonomous restrictive measures that had previously been suspended under the JCPOA.

On 29 September 2025, the Council of the EU adopted new regulations to reintroduce these measures, which go beyond the requirements of the UN Security Council snapback. This was effected by amendments to various EU legal instruments, including by amending the EU's existing primary Iran nuclear sanctions instrument (Regulation (EU) No 267/2012) by Council Regulation (EU) 2025/1975, Council Implementing Regulation (EU) 2025/1980 and Council Implementing Regulation (EU) 2025/1982.

Key elements of the EU's sanctions include:

• A ban on the import, purchase, and transport of Iranian crude oil, natural gas, petrochemical and petroleum products, and related services.
• Prohibitions on the sale, supply, or transfer of key equipment and technology for the energy, petrochemical, and naval sectors, as well as certain software and precious metals, diamonds, and graphite.
• Freezing of assets belonging to the Central Bank of Iran and major Iranian commercial banks and actors including the National Iranian Oil Company and National Iranian Gas Company, alongside broader financial and investment restrictions.
• Bans on Iranian cargo flights accessing EU airports and prohibitions on the maintenance or servicing of Iranian cargo aircraft or vessels carrying prohibited materials or goods.
• Restrictions on financial transactions, including enhanced due diligence and notification or authorisation requirements for transfers of funds to and from Iranian persons, entities, or bodies.
• Prohibitions on the provision of insurance and reinsurance to Iranian entities, with limited exceptions for humanitarian purposes.

The EU’s measures are designed to exert additional pressure on Iran and are more extensive than the UN sanctions, although they do not fully revert to the pre-2015 sanctions regime.

UK sanctions position

In response to the snapback, the UK amended its Iran (Sanctions) (Nuclear) (EU Exit) Regulations 2019 by The Iran (Sanctions) (Nuclear) (EU Exit) (Amendment) Regulations 2025, to reflect the snapback of UN sanctions.

In addition, on 29 September 2025, the Foreign, Commonwealth and Development Office added 71 new individuals and entities to the UK Sanctions List. These individuals and entities are now subject to an asset freeze. They include significant actors in Iran's economy including the National Iranian Oil Company, National Iranian Gas Company and several prominent banks. The UK has issued certain "winddown General Licences" to "manage unintended consequences for UK businesses".

The UK has also said that it "intends to bring in legislation to impose further sectoral measures. In line with our partners, this will target finance, energy, shipping, software, and other significant industries which are advancing Iranian nuclear escalation". We anticipate that the UK will move to align its sanctions legislation with the measures adopted by the EU.

Advice for Businesses

The practical effect of the reimposed measures depends on the extent to which businesses are dealing with the targeted Iranian sectors, or designated individuals or entities. Many businesses who have previously disengaged from Iran, or have no involvement with sectors or designated targets, will not be affected.

Despite this, businesses with any exposure to Iran, or Iranian persons, must exercise vigilance and conduct thorough due diligence.

Key points for compliance include:

• Screening all counterparties, transactions, and supply chains against updated EU, and UK sanctions lists to ensure no dealings with designated individuals or entities, or entities owned or controlled by the same.
• Reviewing and, where necessary, freezing any accounts, funds, or economic resources held for designated persons or entities.
• Ensuring that no funds or economic resources are made available, directly or indirectly, to or for the benefit of designated persons, unless a licence or exception applies.
• Assessing all trade, investment, and financial activities for potential links to prohibited sectors, goods, or services, particularly those related to Iran’s energy, petrochemical, military, and nuclear industries.
• Notifying or seeking authorisation from the relevant authorities for any transactions that may fall within the scope of the sanctions, especially for transfers of funds, provision of services, or execution of pre-existing contracts.
• Keeping abreast of further developments, as both the EU and UK may expand their sanctions regimes in response to Iran’s actions or international developments.

Failure to comply with sanctions can result in criminal penalties. If there is any uncertainty regarding the application of the new measures, do not hesitate to reach out to any of our key contacts below.

Other author: Rebecca Akroyd, Junior Associate