Works below mean high water and the marine licence
Planning runs seaward to low water and marine licensing runs landward to mean high water springs, so the intertidal zone sits in both. Neither consent authorises what the other covers.
Development on the foreshore usually needs two consents, not one. The terrestrial planning system runs seaward to the low water mark, and the marine licensing regime under the Marine and Coastal Access Act 2009 runs landward to mean high water springs. Between those two lines the regimes overlap, so a slipway, a jetty, an outfall or a sea defence in the intertidal zone can require planning permission from the local planning authority and a marine licence from the Marine Management Organisation for the same works.
Below mean low water, planning permission drops away and the marine licence carries the whole load. Above mean high water springs, the reverse.
Where the planning boundary stops
A local planning authority's area extends to the low water mark, so the terrestrial system reaches down the beach. The marine plan area begins at mean high water springs and runs seaward. The intertidal strip between them sits inside both.
That overlap is not a drafting accident. It reflects the fact that structures on the foreshore affect land use, amenity and coastal processes at the same time as they affect navigation, the seabed and marine ecology, and different bodies are equipped to assess each.
Establish the two lines on a survey before anything else. Mean high water springs and mean low water are plotted on Ordnance Survey mapping, and on a shallow beach the horizontal distance between them can be hundreds of metres. Where a structure crosses one of the lines, both regimes apply to the parts on either side, which means one design and two applications.
Ownership is a third question again. The Crown Estate owns most of the foreshore and virtually all of the seabed below mean low water, so a lease or licence from the landowner is needed alongside the statutory consents. That is a property transaction with its own timetable, and it is frequently discovered late.
Which activities need a marine licence
The 2009 Act lists licensable marine activities. The categories that matter for development are the deposit of any substance or object in the sea or on or under the seabed, the removal of substances or objects, the construction, alteration or improvement of any works in or over the sea or on or under the seabed, and dredging.
Read those broadly. Driving piles, laying a pipe, placing rock armour, installing a pontoon, removing an old structure and disposing of dredged material all fall within them. So does the disposal of the arisings, which is a separate licensable activity from the dredging itself and is frequently forgotten in the programme.
There are exemptions, set out in the exempted activities order, which cover a range of small-scale and maintenance operations subject to conditions and, in many cases, a requirement to notify the licensing authority before proceeding. An exemption is not the same as nothing to do. Most require registration, and relying on one without registering leaves the activity unlicensed.
Ask the licensing authority directly whether a licence is needed. It answers that question, it answers it in writing, and the answer is worth having on file.
How the two regimes overlap in practice
The two consents test different things through different lenses.
| Planning permission | Marine licence | |
|---|---|---|
| Decision maker | Local planning authority | Marine Management Organisation |
| Policy framework | Development plan and national planning policy | Marine Policy Statement and the relevant marine plan |
| Main concerns | Land use, amenity, design, access, coastal change policy | Navigation, the marine environment, other sea users, seabed effects |
| Environmental assessment | Town and country planning EIA regulations | Marine works EIA regulations |
| Publicity | Site notice, neighbour notification, consultees | Public register, consultation period, statutory consultees |
Neither decision binds the other. A marine licence does not authorise development requiring planning permission, and planning permission does not authorise a licensable marine activity. Applicants sometimes assume the second consent will follow the first as a formality. It does not, and the marine authority is not obliged to take the planning decision into account beyond treating it as a fact.
Environmental information for each
Environmental impact assessment applies through two separate sets of regulations. Works requiring a marine licence are screened under the marine works regulations, while development requiring planning permission is screened under the town and country planning regulations. A scheme spanning the boundary can be caught by one, both or neither.
Where both apply, the sensible approach is a single environmental statement addressing both regimes, with a clear statement of which chapters answer which screening. The alternative, two documents with different baselines, invites both authorities to query the inconsistency. Where the works engage a European site, the habitats assessment must also be done, and the marine authority and the local planning authority are each competent authorities for their own decision. A combined Environmental Impact Assessment must be prepared by competent experts under the relevant regulations, and coastal work is a specialist field within that.
Coastal change policy sits on the planning side. Where the site lies within a coastal change management area identified in the development plan, the policy tests on development in that area apply to the planning application and a Flood Risk Assessment addressing tidal flood risk, wave overtopping and the design life of the structure will be expected.
Sequencing the applications
There is no single right order, but there is a wrong one, which is applying for planning permission with a design you have not tested against the marine authority's concerns.
- Establish the tidal lines, the ownership and the designations, including any protected marine site.
- Take pre-application advice from both authorities, separately, and tell each that you are speaking to the other.
- Secure the Crown Estate position in principle, because a scheme without a property agreement may not be determinable.
- Carry out the surveys that both regimes will want, so the same data supports both applications.
- Submit both applications in parallel, cross-referencing them by reference number.
- Manage the consultation responses together, because the same consultees appear on both.
Running them in parallel is usually faster and it exposes conflicts while the design can still absorb them.
Where conditions collide
The commonest conflict is timing. Marine licences frequently restrict piling and dredging to seasonal windows to protect migratory fish, spawning grounds or marine mammals, and impose noise management requirements during those operations. A planning condition restricting construction hours for residential amenity, or a highways condition on delivery timing, can leave a very narrow window where all the restrictions are satisfied at once.
Other recurring conflicts involve lighting, where navigation requirements push towards conspicuous marking and amenity or ecology policy pushes the other way, and materials, where a design officer wants one finish and the marine authority is concerned about leaching or colonisation.
Identify these at pre-application and propose consistent wording to both authorities. An applicant who presents each with the other's draft condition generally gets a workable outcome. One who discovers the conflict after both consents are issued is applying to vary something.
Documents that serve both applications
Plan the survey programme once. The material both regimes tend to want includes a bathymetric and topographic survey tied to chart datum and Ordnance Datum, a navigational risk assessment where vessels are affected, sediment sampling and analysis where material is to be dredged or deposited, an intertidal and benthic ecological survey, a water quality assessment under the relevant river basin regime, and a marine and coastal archaeological assessment.
That last one is regularly underestimated. The intertidal zone and the seabed hold wreck, submerged landscapes and palaeoenvironmental deposits, and an Archaeological Desk-Based Assessment that covers only the terrestrial record will be sent back. Where the site adjoins a working waterfront, check the safeguarding position as well, since the rules on safeguarded wharves and water transport sites can constrain what may be built even where both consents would otherwise be available.
This is general guidance, not legal advice. Check the position with your local planning authority, the Marine Management Organisation and a qualified coastal engineer before relying on it.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. Environmental impact assessment work must be carried out by competent experts, and an AI-assisted draft is a starting point for those experts rather than a substitute.
Frequently asked questions
Where does planning permission stop and marine licensing begin?
A local planning authority's area extends to the low water mark, and the marine plan area begins at mean high water springs. The intertidal strip between the two lines falls within both regimes, so works there can need planning permission and a marine licence. Below mean low water the marine licence carries the whole load.
Which activities need a marine licence?
The Marine and Coastal Access Act 2009 lists licensable activities including depositing substances or objects in the sea or on the seabed, removing them, constructing, altering or improving works in or over the sea or on the seabed, and dredging. Piling, laying pipes, placing rock armour, installing pontoons and disposing of dredged material all fall within those categories.
Does a planning permission cover the marine licence requirement?
No. The two consents are granted by different bodies under different legislation and neither binds the other. A marine licence does not authorise development requiring planning permission, and planning permission does not authorise a licensable marine activity. The marine authority is not obliged to follow the planning decision beyond treating it as a fact.
Do I need a separate environmental statement for each regime?
Not necessarily, and it is usually better not to. Marine works are screened under the marine works environmental impact assessment regulations and terrestrial development under the town and country planning regulations. Where both apply, prepare one environmental statement addressing both, stating clearly which chapters answer which screening, rather than two documents with different baselines.
Who owns the foreshore and seabed?
The Crown Estate owns most of the foreshore and virtually all of the seabed below mean low water, so a lease or licence from it is needed alongside the statutory consents. That is a property transaction with its own timetable and it is frequently discovered late. Secure the position in principle before submitting either application.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.