Navigating marine licensing prosecutions

read time: 6 mins read time: 6 mins
22.07.25 22.07.25

A marine licence is a consent granted under the Marine and Coastal Access Act 2009 (MCAA 2009), which permits marine licensable activities to be carried out.

The objective is clear: to protect the marine environment. 

As is noted below, what constitutes a marine licensable activity is extremely broad in scope and failure to hold a licence or comply with the conditions of a licence, makes that individual liable to criminal prosecution. 

There are two key regulators who take marine licensing decisions in England and Wales: the Marine Management Organisation (MMO), covering English inshore and offshore regions and the Welsh offshore regions and Natural Resource Wales, covering the Welsh inshore region.

In this article, we outline when a marine licence is needed and the circumstances when individuals could face criminal prosecution.

When is a marine licence needed? 

Under the MCAA 2009, a marine licence is required for ‘licensable activities’ taking place up to the mean high water spring tide mark, including tidal estuaries, rivers and channels, unless an exemption applies. 

The definition of ‘licensable activities’ is found at section 66 of the MCAA 2009 and is notably wide, including:

  • Construction, alteration or improvements of any works in or over the sea or on or under the seabed - this description can encompass the maintenance of existing works 
  • Dredging 
  • Deposit, removal or incineration of any substance or object 
  • Scuttling of any vessel or floating container 

In short, it would be safe to assume that if you're carrying out any activity below the mean high water line, you need a marine licence. It's important to remember this is whether or not the area in question is currently under water and includes structures such as quay walls, piers, private slipways and even balconies projecting over tidal waters. Activities within docks if, when dock gates are open, would let tidal water flow through, are also caught by the regime. 

Due to a lack of awareness, sometimes the first time an individual or organisation realises that they require a marine licence, is when they either receive a visit from the regulator or a letter inviting them to an interview under caution in relation to carrying out licensable activities without a marine licence. 

There are exemptions to the licensable activities. In England they are listed in the Marine Licensing (Exempted Activities) Order 2011 which include, amongst others, activities such as fire fighting, emergency responses and certain fishing operations. For more information exemptions and whether you need a marine licence (in England), please read here.

Prosecutions 

Failure to hold a licence 

The law is simple. If you carry on a licensable marine activity or cause or permit any other person to carry on such an activity, except in accordance with a marine licence, you will be in breach of Section 65(1) MCAA 2009 and liable to prosecution. 

This is a serious offence and can result in criminal, as well as civil, prosecution, with a person found guilty liable, under Section 85(4):

  1. On summary conviction to a fine not exceeding £50,000. 
  2. On conviction on indictment, to a fine or to imprisonment for a term no exceeding two years or to both. 

Therefore, the most serious offences can result in unlimited fines and a two year prison sentence. 

The MMO has issued statutory guidance on its Compliance and Enforcement Strategy which sets out its approach to compliance, including enforcement and monitoring of marine licences. This confirms that it will target high risk areas, such as those in or adjacent to a marine protected area, those involved in novel or complex activities and/or those with a previous history of non-compliance. If your activities fall within such an area, you should ensure that you have the requisite licence. 

Enforcement notices 

Separately, the regulator has the power to issue:

  • Variation, revocation or suspension notices (Section 72) – if a person holds a marine licence but there is a breach of any of the licence provisions or for any reason as the MMO sees relevant, they may vary, suspend or revoke a licence. 
  • Compliance notice (Section 90) – if a person holds a marine licence but has failed, or is failing, to comply with the conditions of the licence. 
  • Remediation notice (Section 91) – if a person holds a marine licence but the carrying on of the activity has caused or is causing, or likely to cause: harm to the environment, harm to human health or interference with legitimate uses of the sea.
  • Stop notices (Section 102) – if a person holds a marine licence but the carrying out of the activity is causing, likely to cause or there is an imminent risk of serious harm to the environment, serious harm to human health or serious interference with legitimate uses of the sea.  
  • Emergency safety notices (Section 104) – if a person holds a marine licence but it appears to an enforcement authority that serious interference with legitimate uses of the sea is occurring, or is likely to occur as a result of any works for the carrying out of which a marine licence is or was needed or any substantial and unforeseen change in the state or position of such works. 

The regulator’s power to issue notices is wide-reaching and in particular, their power to vary, revoke or suspend a notice for 'any other reason that appears to the authority to be relevant' should not be underestimated. 

Importantly, failure to comply with a compliance, remediation, stop or emergency safety notice is a serious criminal offence in itself and again, the most serious offences can result in unlimited fines and a two year prison sentence (Sections 92(4), 103(4) and105(4)). 

If you're issued with a notice, you must comply with its terms immediately. Should you disagree with enforcement action taken, remember your right to appeal against a decision under Section 71 and take legal advice as soon as possible. 

Proceeds of Crime Act 2002

The MMO make clear in their guidance that, where appropriate, they may instigate proceedings under the Proceeds of Crime Act 2002 following conviction of persons for marine licensing offences where that person has gained financially from the crime. If successful, this would deprive offenders of the unlawful financial benefit of their criminal activity and also act as a deterrent for others doing the same for financial gain. 

Conclusion  

Organisations must ensure that work is properly planned, approved and carried out in accordance with the licence requirements. Failure to do so may result in environmental harm and criminal prosecution against an organisation or individual. If you're the subject of MMO enforcement action or have any questions around marine licensing applications or requirements, please contact Lara Moore or Zoe Hunt.

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