M4 motorway diversion around Newport, Gwent

Tagged with: Casework status: Open Casework type: Transport Site designations: SAC Site designations: SSSI
Water vole, Arvicola amphibius, Peak District, UK


An M4 motorway diversion around Newport, sometimes called the “M4 relief road”, has been considered since the early 1980s. The Welsh Government consulted on draft Orders for the development of the diversion (also known as ‘the Black route’, following previous consultations on route options) last year. Thousands of objections were submitted, including over 5000 by RSPB supporters, and consequently the Welsh Government announced a local public inquiry which opened on 28 February 2017.

The RSPB has submitted written evidence to the public inquiry emphasising our objection to the proposal. We are objecting because the new section of motorway would cut through four of the Gwent Levels Sites of Special Scientific Interest (SSSIs), destroying and fragmenting habitats. It will destroy the area used by a pair of common crane which returned to breed on the Levels last year; the first in Wales for 400 years, and it will jeopardise the future of one of the UK’s rarest bees, the shrill carder bee.

The proposal runs contrary to the Welsh Government’s specific legal duties relating to SSSIs and its duties to biodiversity under the Environment (Wales) Act 2016. It is also contrary to the requirements and the spirit of Wales’ world-leading Well-being of Future Generations Act, which calls for a new approach recognising the importance of the environment to Wales’ future well-being.

In case of the worst possible outcome – the Welsh Government eventually deciding to proceed with the development of the M4 diversity following the inquiry – we are also providing evidence as to what would be needed to mitigate and compensate for these impacts; the proposals currently offered by the Welsh Government on this score are woefully inadequate.

Wales’s Future Generations Commissioner, Sophie Howe, also spoke out against the M4 diversion in February 2017, saying: 

“I believe that using the Welsh Government's borrowing powers to finance one scheme that will, at best, result in geographically, economically and socially disproportionate benefits to one part of Wales is ill-conceived. Building roads is what we have been doing for the last 50 years and is not the solution we should be seeking in 2017 and beyond. The rationale for a new road was conceived over 25 years ago with the main purpose of addressing congestion in the area. I do not agree with the basic premise that this is the 'most sustainable, long-term solution to current social, environmental and economic problems associated with this route."


Why is it worth fighting for?

We are concerned about the current M4 proposals because, in our opinion, it would damage the fragile wetlands of the Gwent Levels.

It's not just the road itself which would have an effect, but there would be damage indirectly through isolating parts of the Gwent Levels from the main body of the wetland, causing fragmentation of this important habitat. Furthermore, it could seriously harm the wetlands' water supply, and pollute the watercourses upon which the wetlands rely.

We are also worried about the precedent this huge project would set in terms of a move away from sustainable transport to car-borne transport, with the resultant increases in greenhouse gases.

We think the Welsh Government has not properly looked at more environmentally-acceptable alternatives to this project, and has not taken into account the fact that traffic levels on the existing M4 have remained more or less static for several years. We further consider that the project goes against the aims of the recent Well-being of Future Generations Act.

How you can help

Campaign with us. 

Contact campaigns.wales@rspb.org.uk if you would like to get involved with our M4 campaign activities, or join as a campaign champion to receive monthly updates about all of our campaigns in Wales.

Gwent Levels RSPB Reserve, aerial view

Our position

The current version of the M4 proposal would be located along the most damaging route option, called the "Black Route".

Consultants for Welsh Government have recently finished scoping what ecological surveys and research are needed to produce an Environmental Impact Assessment (EIA – a legal requirement under EU law for a development of this scale) to assess the environmental impacts of the Black Route.

During this period, RSPB Cymru has been working with other environmental bodies, particularly Friends of the Earth Cymru and the Gwent Wildlife Trust, as well as local communities, to influence Welsh Government. Our preferred option is that Welsh Government rejects a diverted and expanded motorway around Newport altogether, as we believe there are numerous, more sustainable transport options either already being carried out, or in the pipeline, such as the South Wales Metro.

While the Welsh Government is pushing ahead with the official legal steps needed to make the M4 motorway diversion a reality, a number of serious question marks hang over the future of the project:

  • There will have to be an official public inquiry into the project, which the Welsh Government must win if it is to proceed. This is the stage when objections, including those on environmental grounds and damage to the protected sites, will be considered.  
  • The total cost of the motorway is uncertain. Indications frequently leave out costs like VAT, inflation and maintenance, meaning the project could cost considerably more than the £1.1bn price tag quoted in March 2016.
  • While officially, the Welsh Government supports the M4 motorway diversion there is no consensus in the Welsh Assembly.


  • 28 February 2018 - present
    Local Public Inquiry in progress at Lysaght Institute, Newport. RSPB provided detailed written evidence and has attended a site visit with the Inspector to demonstrate our concerns. 
  • 2016
    Welsh Government consulted on draft orders and they received thousands of objections, including over 5,000 from RSPB supporters. This led to the Government opening a Local Public Inquiry.
  • 10 - 12 March 2015
    Judicial Review of the Welsh Government's plans to build a new £1 billion motorway across the protected Gwent Levels.
  • 23 September 2014
    Legal challenge launched by Friends of the Earth Cymru against the Welsh Government’s decision to build the £1 billion motorway through the Gwent Levels.
  • 16 December 2013
    Public consultation ends (see Useful links)
  • 23 September 2013
    Consultation on upgrade to M4 around Newport opens
  • 26 June 2013
    Welsh Government Minister for Transport Edwina Hart AM announced the Government's intention to consult later in the year on a new motorway to the South of Newport
  • 6 March – 6 July 2012
    Welsh Government Consultation on M4 Corridor Enhancement Measures

Further reading