I would think the issue is, whether or not an inland waterway, especially one not using sea water, is a "Marine Environment". I suppose it might be possible that there is provision in some legislation that defines "marine" to encompass the UK's inland artificial waterways that are not navigable by shipping, but if such legislation exists, I would have thought that someone on this forum would have drawn attention to it. Surely the normal meaning of "marine" is something relating to the sea? My dictionary defines "marine" as: Of or pertaining to the sea; maritime Native to, existing in, or formed by the sea Intended for use in sea or in navigation; nautical; naval, marine currents, marine law. Shipping or shipping interests generally A picture or painting of the sea ++++++++++++++++ The Government's " Clean Marine Plan" document (July 2019) does not address canals, only shipping, and its glossary includes the following definitions: Domestic Shipping - ships which have come from a UK port and are making a call at a different UK port. Domestic shipping for the purposes of the UK GHG inventory is defined as any direct journey from a UK port directly to another UK port. In the case of shipping between the UK and its overseas territories ..... these are treated as a domestic journey for the sake of International shipping emissions and are not included in the UK total greenhouse emissions. ..... (they are to be reported as a memo item) International shipping - ships calling at a UK port which have come from or are going to an international destination. ++++++++++++++++ So in this official government document at least, "Marine" clearly relates to the Sea. +++++++++++++++++ Likewise, the government document "Maritime 2050", not a law, but a rather long, and somewhat verbose statement of objectives that they would like to happen, is all about sea-going vessels. Paragraph 45. Maritime 2050 is concerned with the impact on the marine and the immediate coastal environment. So prima facie not concerned with inland vessels such as narrowboats . Paragraph 5.6 starts with: Domestically, the UK maritime sector is governed by regulation set out in the Merchant Shipping Act 1995. I doubt that that Act covers inland waterways that are not navigable by merchant shipping. A brief mention of the growth in leisure activities goes on to say: "This is just the start of encouraging more people to interact with the sea for leisure ...... (emphssis added). The people involved in shipping as crews or officers, are referred to as "seafarers" . ++++++++++ I spent many years working in the legal profession, and one thing I learned is that, while Parliament makes laws, you cannot definitely know what their provisions mean until they have been legally interpreted by the highest court whose decisions are not subject to appeal, formerly the House of Lords, latterly the Supreme Court. In my field there was more than one case where everyone thought they knew what the legislation meant, but the courts decided it meant something different. In one case that I am aware of Parliament had to amend the relevant Act to make it mean what the government had intended it to mean.