Key takeaways
Sanctions and the shadow fleet
UK port authorities should have established sanctions procedure and should perform their due diligence.
UK maritime services ban
This will likely affect maritime logistics services offered by UK ports.
UK zero tolerance policy
Deliberate or negligent sanctions breaches can result in significant financial penalties and reputational damage.
The topic of shadow fleet vessels has dominated headlines in January 2026 as a result of the US seizure of a number of oil tankers linked with Venezuela and/or Russia and/or Iran.
One of these vessels, the Marinera, was seized with the assistance of UK armed forces in the North Atlantic, raising the question as to which port she may be diverted to and what the regulatory and wider repercussions may be for the port.
The UK backed the operation, maintaining it was lawful because the vessel was breaching international sanctions. UK Government ministers have cited the provisions of the 2018 Sanctions and Anti-Money Laundering Act, arguing that they permitted the use of military force against oil tankers operating without a valid national flag – a common tactic used to evade sanctions enforcement.
It has also been reported that the UK is contemplating joint action with EU member states to board and question suspected shadow fleet vessels. Some EU states have already commenced such action, boarding shadow fleet tankers and inquiring about insurance and flag status.
Yet, despite these interventions, shadow fleet tankers are still actively operating in breach of sanctions. Common tactics used to evade interception include name changes, ownership changes, flag hopping, using flags of convenience, STS transfers to disguise cargo origin and going dark (switching off the AIS transmitters). It has been estimated that one in five oil tankers worldwide are used to smuggle oil and evade sanctions.
The regulations
Since March 2022, the UK Government has blocked entry into its ports by any Russian-linked vessels, to encompass vessels that are:
Owned, controlled, chartered or operated by any person connected with Russia
Owned, controlled, chartered or operated by Designated Persons
Flying the Russian flag
Registered in Russia
These prohibitions were enshrined in the Russia (Sanctions) (EU Exit) (Amendment) (No. 4) Regulations 2022, pursuant to which Russian vessels and other vessels specified by the Secretary of State for Transport cannot enter UK ports.
Further, the Secretary of State and harbour authorities have the power under the Regulations to issue port barring orders and movement directions, detain Russian vessels and direct the UK Ship Registry to refuse to register any Russian-linked vessel.
From December 2022, the UK banned the maritime transportation of Russian oil and from February 2023 the maritime transportation of refined oil products.
At the same time, the Government banned the provision of ‘associated services’ that facilitated the maritime transportation of Russian oil and refined oil products, aimed at financial and brokering services rather than purely maritime services such as bunkering or flagging.
Most recently, in November 2025, the UK Government announced it would be introducing a new ‘maritime services’ ban on Russian LNG exports. This ban will prohibit UK-linked vessels, insurers and other service providers from being involved in the carriage of Russian LNG to third countries. The maritime services ban will be phased in during 2026 in coordination with the EU.
Although the details of the proposed maritime services ban have not yet been published, insurers will clearly be covered by the ban. In addition, the ban will also likely extend to a range of maritime service providers, including ship management, crewing, marine consultants and surveyors.
It is worth considering in this context the fact that UK ports also offer a wide range of maritime logistics services, which can include port operations, stevedoring and labour, agency services such as crew support, cargo management, vessel handling, berthing, mooring, pilotage and tug assistance. It will therefore be interesting to see the extent to which such port-based services are impacted by the ban.
Sanctions listings
The UK, EU and US have lists of sanctioned entities, individuals and vessels.
As of 28 January 2026, there is only one UK Sanctions List for all UK sanctions designations. As this List is kept updated when there are any changes or additions in relation to the Designations, it is incredibly long and not limited to just Russian, Venezuelan or Iranian entities, individuals or entities. Accordingly, it is the List to consult to check for any sanctions designations.
As at January 2026, there were 520 sanctioned vessels listed.
UK ports: precautions, preparation and response
Under s.33 of the Harbours, Docks and Piers Clauses Act 1847, UK port authorities have a legal duty to permit eligible vessels entry into port. They must continue to do this, while still applying sanctions regulations to affected vessels.
The 2019 Regulations specifically require that ports must not provide a ship access to a UK port if they know, or have reasonable cause to suspect, that the ship is:
owned, controlled, chartered or operated by a designated person;
owned, controlled, chartered or operated by persons connected with Russia;
flying the flag of Russia;
registered in Russia; or
ship otherwise specified.
UK port authorities have therefore introduced sanctions procedures to determine whether particular vessels come within scope of the Regulations, from which they can decide whether to refuse or allow a vessel entry to the port based on the criteria set out in the Regulations, using available databases.
Where the available data is unclear, the port authority may delay the vessel while it seeks Department for Transport guidance on whether or not to admit the vessel to the port.
The port authority and related services providers should therefore conduct a risk-based sanctions check on the vessel and her owners / operators, associated companies, related individuals, cargo owners and other cargo interests, agents and all customers involved in the shipment arriving at the port. It is also advisable to conduct a separate sanction check for each service-based transaction (docking, discharge / loading of cargo etc).
Insofar as reasonably possible, UK port authorities should:
Identify all relevant parties, obtaining all available vessel details;
Check the UK Sanctions List and other relevant sanctions lists that are publicly available;
Check ownership and control, including opaque corporate structures and any concealment of beneficial ownership;
Investigate vessel history – particular attention should be paid to the vessel’s last three voyages, whether there has been a change of owner / operator / flag that might be suspicious and whether previous voyages have been to or from sanctioned countries or involved potentially sanctioned cargoes.
Check the declared cargo details – copies of export licenses, bills of lading (detailing the parties and the cargo’s origin and destination) and other shipment documents should also be requested and inspected in order to ensure the cargo is not prohibited or linked to sanctioned activities.
Ensuring due diligence
These are, however, no more than general guidelines.
In order to ensure it has satisfied its due diligence obligation with regard to sanctions checks and screening, any port authority that has not established comprehensive sanctions check procedures should do so without delay.
Obtaining legal advice on what the due diligence obligation requires and getting expert third-party guidance on what the sanctions check procedure should entail and assistance in establishing and implementing the procedure, are also to be recommended.
It is also key to remain informed on all sanctions developments and changes in the applicable regulations and requirements, which is where legal advice can be of huge assistance.
Penalties and reputational damage resulting from sanctions breaches (even if inadvertent or careless, rather than deliberate), can be severe. The financial expense to a port authority of ensuring it is sanctions-compliant is more than offset by the advantages and is also a legal requirement.
Comment
Whilst there is clear a commercial downside to limiting vessel calls and the use of the associated port and related maritime services, the UK has a zero-tolerance policy towards deliberate or negligent breaches of sanctions regulations.
Equally, UK-backed actions against shadow fleet vessels in UK territorial waters (that ultimately result in diversion to UK ports) raise a host of questions around how such vessels can be serviced by the port and associated service providers.
