The BBC has a video in which those opposing Greenpeace say so

A Greenpeace ship has been dropping huge boulders into the sea off Brighton this week to stop fishing boats from trawling the sea bed. [...]

But leaders of the fishing community describe the action as dangerous, illegal and irresponsible.

What UK law prohibits this and what is the penalty for breaking it?

  • 3
    Possibly causing a danger to shipping or similar contrary to maritime law, but it will take a bit or research. BRB.
    – user35069
    Feb 26, 2021 at 8:52
  • They are doing it to deter illegal fishing, not that two wrongs make a right. If they are outside territorial waters, who has jurisdiction? Feb 26, 2021 at 23:49
  • 1
    @MichaelHarvey they may or may not be outside territorial waters, but they are certainly within the exclusive economic zone.
    – phoog
    Feb 27, 2021 at 0:32
  • FWIW, on the BBC video at 1:45 you can hear a voice announcing (presumably to the Greenpeace vessel) that "You do not have a marine license granted under part 4 of the Marine and Coastal Access Act 2009 to undertake(?) this activity." Dec 24, 2022 at 17:32

1 Answer 1


The sea area in question is a Marine Protected Area, which is referred to in the as a Marine Conservation Zone (as per No17 on the 2016 linked list) and lies within the UK's territorial waters.

What UK law prohibits this?

I have discounted my initial thoughts about s.58(2) of the Merchant Shipping Act 1995 as I strongly suspect the Greenpeace vessel is neither UK registered nor proceeding to/from a UK port.

I have also considered the Criminal Damage Act 1971 which, although potentially viable* and having off-shore jurisdiction, I have discounted in favour of the Marine and Coastal Access Act 2009 which creates the offence of depositing objects in the UK's territorial waters without a licence:

s.65 Requirement for a Licence

(1) No person may -

(a) carry on a licensable marine activity ... except in accordance with a marine licence granted by the appropriate licensing authority.

s.66(1) Licensable Marine Activity includes:

1.(a) To deposit any substance or object within the UK marine licensing area, either in the sea or on or under the sea bed, from ... any ... vessel ...

s.66(4) states the "UK marine licensing area” consists of the UK Marine Area which is defined by s.42 to include:

the area of sea within the seaward limits of the territorial sea adjacent to the United Kingdom

What is the penalty?

s.85(4) states anyone guilty of a s.65(1) offence is liable:

(a) on summary conviction, to a fine not exceeding £50,000,

(b) on conviction on indictment, to a fine or to imprisonment for a term not exceeding two years or to both.

*relating to the seabed as well as the bottom trawlers.

  • There's no need to discount the Criminal Damage Act if the deposition of the boulders violates the Marine and Coastal Access Act. It's entirely possible that the activity in question violates both acts.
    – phoog
    Feb 27, 2021 at 4:18

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