Significant infrastructure projects (SIPs): the role of Cadw, Heneb and the RCAHMW

Applicants should engage early with heritage bodies if a significant infrastructure project (SIP) could affect the historic environment.

Early engagement can help applicants:

• identify heritage issues
• understand what surveys or assessments may be needed
• reduce the risk of delays after submission
• address issues before an application is examined

The historic environment can include:

• scheduled monuments
• listed buildings
• registered historic parks and gardens
• registered historic landscapes
• protected wrecks
• World Heritage Sites
• archaeological remains
• historic battlefields
• the setting of historic assets

Planning and Environment Decisions Wales (PEDW) and Cadw encourage applicants to engage early with Cadw and other heritage bodies before they submit an application. 

Cadw is the Welsh Government’s historic environment service. It works to protect the historic environment in Wales and make it more accessible. 

The Welsh Ministers (in practice, Cadw) are a statutory consultee in the infrastructure consenting process. This is set out in Paragraph D of Schedule 1 of The Infrastructure Consent (Pre-Application and Application Procedure and Transitional Provisions) (Wales) Regulations 2025 (“the pre-application regulations”). 

On land 

Cadw’s responsibilities cover the whole of Wales. This includes protecting the historic environment and the setting of the heritage assets.

At sea 

Cadw’s responsibilities include underwater archaeology in the Welsh area of the UK Territorial Sea. This is under the National Heritage Act 1983 (as amended*). 

*Amended by the National Heritage Act 2002, s.1

The grant of infrastructure consent removes the need for certain separate consents. 

This includes some consents under: 

• the Historic Environment (Wales) Act 2023 
• the Protection of Wrecks Act 1973 (Section 20.1.c i-iii of 2024 Act)

Any consents needed under the Protection of Military Remains Act 1986 must be referred to the Ministry of Defence.

Most onshore and offshore significant infrastructure projects (SIPs) will have some impact on the historic environment. 

The pre-application stage under the Infrastructure (Wales) Act 2024 allows an applicant to: 

• identify relevant issues
• consult on their proposal
• publicise their proposal
• refine their scheme
• resolve issues before submitting an application

Applicants should consult Cadw on proposed applications that are likely to affect land in Wales and meet the requirements in Paragraph D of Schedule 1 to the pre-application regulations.

Applicants should give Cadw enough information to assess the likely impact of the proposal on the historic environment.

This should include relevant survey data, such as geophysical and geotechnical data, supported by desk-based historic environment information.

Applicants must give Cadw at least 42 days to respond to formal consultations.

Applicants must consider any response Cadw sends before the consultation deadline.

Cadw welcome further consultation with applicants outside of the statutory pre-application consultation process. Cadw will provide further advice where this is requested and appropriate. 

Applicants should explain how they have addressed Cadw’s comments when they submit their final application. 

For proposed developments in Wales that may have cross-border effects in England, early consultation with Cadw and Historic England will be important. 

Archaeological assessments and fieldwork will be prepared in line with the standards and guidance set by the Chartered Institute for Archaeologists.

The Infrastructure Consent (Fees) (Wales) Regulations 2025 allow Cadw to recover costs for relevant services and engagement linked to a SIP application.

Before submitting an application, developers must gather the necessary heritage information and consult on their proposals. This includes consulting Cadw where required.

Cadw can provide pre-application advice on the likely impact of proposals on the historic environment. Developers should consider this advice before finalising their proposals.

Cadw recommends early engagement where an infrastructure consent application is being considered.

For further information, see Cadw guidance on cost recovery

Cadw is consulted on qualifying Environmental Impact Assessment (EIA) projects for SIPs in Wales. EIA is a process for identifying positive and negative environmental effects of proposed developments before planning permission is granted.

Cadw provides advice on: 

• whether a project is likely to have significant effects on the historic environment and needs an EIA
• the scope of an EIA for the historic environment.

When responding to an EIA, Cadw considers the impact of the project on:

• scheduled monuments and their settings
• listed buildings and their settings
• registered historic parks and gardens and their settings
• registered historic landscapes
• protected wrecks
• World Heritage Sites

Cadw makes assessments in line with Welsh Government land use planning policy and guidance contained in:

• Planning Policy Wales 
• Technical Advice Note 24: The Historic Environment
• Conservation Principles for the Sustainable Management of the Historic Environment in Wales 
• associated guidance published on Cadw’s website

Cadw can consider an applicant’s draft Environmental Statement or any other documents. 

This may include:

• historic environment desk-based assessments and 
• Assessment of the Significance of the Impact of Development on Historic Landscape (ASIDOHL)) 

This can help applicants improve the accuracy of their final documents. 

Scheduled monuments

See locations and details of scheduled monuments on the Cadw website 

Applicants should assess potential impacts on the settings of scheduled monuments using the guidance in Setting of Historic Assets in Wales.

Listed buildings

See: Locations and details of listed buildings on Cadw website. 

Applicants should assess potential impacts on the settings of listed buildings using the guidance in Heritage Impact Assessment in Wales.

Applicants should seek specialist advice from the local planning authority conservation officers on the impact of proposed developments on listed buildings. 

Marine historic environment

The Protection of Wreck Act 1973 protects wrecks below mean high water from interference by unauthorised persons. 

Section 1 protects wrecks thought to be historically, archaeologically or artistically important. It also protects objects contained, or formerly contained, in those wrecks. 

Six sites in Welsh waters are designated under section 1 of the Act. Their locations can be found on Cof Cymru.

Specialist advice on maritime issues can be provided by the Senior Maritime Investigator at the Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW). 

Relevant guidance includes: 

Managing the Marine Historic Environment of Wales

Caring for Coastal Heritage

Registered historic parks and gardens

The Welsh Ministers maintain a statutory register of historic parks and gardens.

Locations and details of registered historic parks and gardens are available on the Cadw website. 

Relevant guidance includes Managing Change to Registered Historic Parks and Gardens in Wales

Historic landscapes

The register of landscapes of historic interest in Wales includes 58 landscapes of outstanding or special historic interest.

These are considered the best examples of different types of historic landscapes in Wales.

A direct impact on a registered historic landscape will usually need an Assessment of the Significance of the Impact of Development on Historic Landscape. 

Where a development may affect the setting of a registered historic asset, appicants should use the guidance in Setting of Historic Assets in Wales.

Battlefields

There is no statutory register of battlefields in Wales.

The Royal Commission on the Ancient and Historical Monuments of Wales maintains The Inventory of Historic Battlefields in Wales. 

Applicants should consider the impact of a proposed development on sites in the inventory as part of any Environmental Statement.

Solar farms

Specific guidance is available on the archaeological assessments needed for large-scale solar farm applications. 

The Archaeology and Solar Farms - Good Practice Guide explains how to assess the impact of solar farm development on archaeology and how to reduce harm.

World Heritage Sites

There are 4 World Heritage Sites in Wales:

• Castles and Town Walls of King Edward in Gwynedd (inscribed 1986)
• Blaenavon Industrial Landscape (inscribed 2000)
• Pontcysyllte Aqueduct and Canal (inscribed 2009)
• The Slate Landscape of Northwest Wales (inscribed 2021)

Guidance on protecting World Heritage Sites is available in Managing World Heritage Sites in Wales.

Applicants should assess the impact of developments on the outstanding universal value of world Heritage Sites using: 

• Guidance on Heritage Impact Assessments for Cultural World Heritage Properties 
• World Heritage Centre - Guidance and Toolkit for Impact Assessments in a World Heritage Context

Cadw contact details 

Email: cadwinfrastructure@gov.wales

Telephone 0300 025 6000

Address: Cadw, Welsh Government, Rhydycar Business Park, Merthyr Tydfil, CF48 1UZ

Sections 194 and 195 of the Historic Environment (Wales) Act 2023 require the Welsh Ministers to maintain a publicly accessible HER for each local authority area in Wales. 

Heneb: The Trust for Welsh Archaeology maintains the HER on behalf of the Welsh Ministers.

The Archwilio website provides online access to the historic environment records for each local authority area. This may be enough for initial appraisals. 

However, Archwilio does not provide access to the full HER., Applicants should contact the HER directly to check whether there is further information that is not available online.

Charging rate for commercial enquiries are available on the Heneb website.

Role of Heneb: The Trust for Welsh Archaeology

Heneb: The Trust for Welsh Archaeology maintains the Historic Environment Record on behalf of the Welsh Ministers.

Heneb’s Archaeological Planning Service provides specialist and impartial archaeological advice to the local planning authorities in Wales. It advise on the scope of archaeological work needed for development proposals and monitors archaeological projects.

Cadw delegates responsibility for advice on the impact of development on non-designated historic assets to Heneb. This includes advice on whether on-site investigation is needed and monitoring fieldwork. 

Applicants should consult Heneb during the pre-application stage and at later consultation stages where relevant.. Charging rates can be found on the Heneb website.

For more information about Heneb’s wider role, see: About Heneb | Heneb

Heneb contact details

Historic Environment Record: 01639 501702 her@heneb.org.uk

Archaeological Planning Service: 01248 366975 planning@heneb.org.uk

The Royal Commission on the Ancient and Historical Monuments of Wales (RCAHMW) develops and promotes understanding of Wales’ archaeological, built and maritime heritage.

The RCAHMW holds the The National Monuments Record of Wales. This includes photographs, maps, images, publications and reports.

Applicants can search this archive using Coflein or by contacting RCAHMW’s enquiry service.

The RCAHMW is a statutory consultee for marine licensing in Wales. 

The Senior Investigator (Maritime) of the RCAHMW provides specialist advice on the effect of development on marine historic assets. 

For infrastructure consent applications, RCAHMW can provide non-statutory advice on works that are: 

• in the offshore zone, the area beyond the low water mark
• in the inter-tidal zone
• across both the offshore and intertidal zones

This advice can apply to works up to the continental shelf boundary, not only the 12-mile territorial limit.