Oxford to Cambridge Expressway

Tagged with: Casework status: Open Casework type: Transport Site designations: SAC Site designations: SSSI


The Oxford-Cambridge Expressway threatened some of the most important places for nature in Oxfordshire and Buckinghamshire and would have made responding to the climate and ecological emergency even more difficult. On 18 March 2021 Government announced the cancellation of the Expressway project, saying it was no longer “cost effective”, marking the end of this imminent threat to nature. We are disappointed though that the adverse environmental impacts of the project did not factor into Government’s calculations and ultimate decision to cancel the Expressway. There is still a need to influence other infrastructure projects being promoted as part of the Government’s ambitions for economic growth in the Oxford-Cambridge Arc. We will continue to engage with the Arc proposals to ensure all future plans for the Arc have the environment at their heart.

Picture credit: Bittern by Paul Wyeth


Why is it worth fighting for?

The area that would have been affected by the Expressway is home to many special and protected wildlife sites, including:

  • Two internationally important Special Areas of Conservation (SAC) south-west of Oxford: Cothill Fen, and Oxford Meadows. These are important for rare plant communities and highly vulnerable to air and water pollution, changes to groundwater, and to surface flooding patterns.
  • Over 30 Sites of Special Scientific Interest (SSSI) – nationally important sites for wildlife, legally protected under the Wildlife and Countryside Act. Among them, the large ancient woodland SSSIs of Bernwood Forest in Buckinghamshire are precious for their butterflies and bats including one of Britain’s rarest mammals: Bechstein's bat.
  • The upper Ray Valley, home to nationally rare and declining species like curlew (breeding) and black hairstreak butterflies. Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT) manage an important group of lowland meadows here, rich in wildflowers and herbs: a habitat almost completely lost from much of England.
  • Where East-West Rail and High Speed 2 intersect lies Calvert Jubilee, another BBOWT nature reserve important for breeding and wintering birds including bittern, and declining butterflies like grizzled skippers.

Further east, the Greensand Ridge is an area of higher ground covered with woodlands and heathlands, home to Woburn Park and a cluster of SSSIs and locally designated wildlife sites.

Curlew Numenius arquata, bathing in shallow pool, Geltsdale RSPB reserve, Cumbria, England

Our position

While the Expressway itself may no longer present an immediate threat to wildlife, and its harmful potential environmental impacts have, for the time being, been avoided, it stands as a cautionary tale for other large infrastructure projects. We urgently need such projects, and the Government that supports them, to start taking seriously their responsibility for protecting and restoring nature and contributing to efforts to address the Nature and Climate Emergency.

Where the Expressway project failed:

  1. Failed to protect nature
    Before the Expressway was cancelled, Highways England’s preferred route corridor was the one with the highest number and density of wildlife sites. Highways England avoided any proper consideration of the relative wildlife value of the alternative corridors when the preferred choice was made, instead making the irresponsible, and incorrect, assumption that any damage could simply be offset (i.e. compensated for) by creating replacement habitat for any that might be lost. That’s not as easy as Highways England seem to think, and in the case of irreplaceable habitats like ancient woodland full compensation is widely seen as impossible.
  2. Failed to consider cumulative impacts
    The Expressway would have had significant and widespread environmental impacts beyond its own construction and operation, through the associated housebuilding it was explicitly designed to enable and cumulative impacts in combination with other major infrastructure projects such as East West Rail (already at an advanced stage of delivery in this part of the Oxford to Cambridge Arc, or ‘Growth Corridor’) and HS2. The failure to carry out Strategic Environmental Assessment for the Expressway, or take a joined-up approach to planning strategic transport infrastructure together with associated housing, would have made it all but impossible to prevent unsustainable impacts on air quality, on water resources that are already over-exploited in places, and from increased recreational pressure in fragmented and isolated wildlife habitats. The Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT) mounted a legal challenge to the Government’s failure to apply Strategic Environmental Assessment (SEA) to the Expressway corridor selection in 2018/19, supported by evidence from the RSPB.
  3. Failed to show how it would help reduce greenhouse gas emissions
    Climate change is the biggest threat to nature and our own way of life, and in May 2019 the UK Government declared a “climate emergency”, having already committed to achieving carbon neutrality by 2050. The Intergovernmental Panel on Climate Change (IPCC) found that we must reduce global carbon output by 45% by 2030 to limit global warming to 1.5°C. Huge reductions in carbon emissions are needed in all sectors, including transport. In the UK, transport makes the largest single contribution to domestic greenhouse gas emission of any sector. We have to act fast or we will face increasing disruption and chaos including, ironically, to our own ability to travel safely and reliably. Alongside partner organisations the RSPB is calling for more urgent action to achieve a zero-carbon transport sector by 2045, if not sooner - in line with the IPCC’s warning.

    At no point did Highways England or the Department for Transport (DfT) properly assess the impact the Expressway would have had on greenhouse gas emissions.

    In 2021, DfT is expected to publish the UK's first Transport Decarbonisation Plan. In stark contradiction to the urgent need to decarbonise the transport sector though, DfT has taken the astonishing decision that the Oxford-Cambridge Arc’s remaining strategic transport infrastructure project, East-West Rail , will not be fully electrified when it opens – instead opting for the initially cheaper, but ultimately far more environmentally and financially costly option of running diesel electric rolling stock when the line first opens.

    This decision flies in the face of Government’s own commitment to decarbonise the transport sector, not to mention local aspirations to work towards net zero by 2040.[1]

    [1] See England’s Economic Heartland’s Transport Strategy https://www.englandseconomicheartland.com/transport/our-strategy/ and Shared regional principles for protecting, restoring and enhancing the environment in the Oxford-Cambridge Arc https://www.semlep.com/modules/downloads/download.php?file_name=2306

How you can help

In March 2021, Secretary of State for Transport, Grant Shapps MP, announced the cancellation of the Expressway, marking the end of the immediate threat to nature from this damaging project.

Government’s ambitions for economic growth in the Oxford-Cambridge Arc, and we will continue to work to ensure they avoid harming nature and maximise their contribution to restoring nature across the Arc.

This summer, Government will be consulting the public on the Vision for the OxCam Arc. It is essential that this Vision has protecting and looking after the natural environment as its guiding principle. Keep an eye on our OxCam Arc campaign page for updates about this consultation and how you can help ensure nature is at the heart of the Vision for the Arc.

In the meantime, if you are keen for your voice to be heard, the RSPB recommends writing to your MP. You could also write to Grant Shapps MP, who is currently the Secretary of State for Transport.

Here are a few over-arching things you could consider mentioning to your MP or the Secretary of State:

  • Strategic Environmental Assessment* ("SEA") should be carried out as a matter of course for all major transport infrastructure projects to ensure that less environmentally damaging options are not excluded from consideration;
  • Assessing and considering the cumulative environmental impacts of transport infrastructure projects together with other forms of development, such as housing, that transport infrastructure enables (often by design) is essential to preventing significant environmental damage, and should be a requirement of all strategic transport infrastructure projects.
  • Only once existing irreplaceable habitats and wildlife sites have been protected, all transport infrastructure projects (including Nationally Significant Infrastructure Projects) should be required to achieve a net gain in biodiversity that contributes to strategic nature recovery.
  • All strategic transport infrastructure projects should be subject to stringent assessment of their lifetime greenhouse gas emissions and a net zero test should be applied to ensure that only projects that are compatible with achieving net zero GHG emissions by 2050 at the latest receive public investment.

    *If you’re confused about SEA and EIA (Environmental Impact Assessment) it's worth knowing that for transport projects EIA is done once a preferred route is chosen and the designs have been well worked up – but by then, different and potentially less damaging alternatives may have been dropped from further consideration. Doing SEA of all the options beforehand can help ensure the best (environmentally) alternatives are identified and worse (environmentally) options can be avoided. For more information visit the government's guidance page here.


  • March 2021
    Government announces cancellation of the Expressway, saying it was no longer “cost effective”.
  • March 2020
    Government announces a pause to further development work on the Expressway, apparently to consider other options to support their aspirations for the Growth Arc.
  • Autumn 2019
    Highways England plan to consult stakeholders and local communities about route options within Corridor B, ahead of choosing a preferred route.
  • September 2018
    The Government announced its preferred corridor, B, but excluded sub-option B2 which included parts of Otmoor. 
  • August 2018
    The RSPB endorsed a letter written on behalf of the Horton-cum-Studley Expressway Group by the Environmental Law Foundation, addressed to the Secretary of State for Transport and to Highways England. The letter asked for an explanation for why Strategic Environmental Assessment hasn’t been done.
  • April 2018
    The RSPB’s response on the corridor options is submitted.
  • February 2018
    After a second meeting of the SRG, Highways England consults the RSPB and other environmental stakeholders on the corridor options.
  • December 2017
    Highways England creates the Strategic Environment Stakeholder Reference Group (SRG) for the Expressway and invites the RSPB to participate.
  • November 2017
    The Chancellor’s autumn budget statement announces 1M new homes to be built in the Oxford to Cambridge Arc.