Oxford to Cambridge Expressway

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


To close a "missing link" in the strategic road network, the Government has proposed a new major road – an Expressway – to reduce journey times between Oxford and Cambridge and to enable development of up to a million new homes across the corridor. Right now we’re waiting for the Government to confirm whether or not this scheme is going to go ahead, following their announcement on 12 March 2020 that further work on the proposal would be "paused". 

Thankfully, the Government has recognised the importance of the Otmoor basin for nature – including our own nature reserve – and excluded it from further consideration. However, the rest of corridor B still includes two internationally important sites and over 30 Sites of Special Scientific Interest, or "SSSIs", and numerous locally important sites including nature reserves managed by the Wildlife Trusts.

Of the three corridors originally proposed, we said Corridor B posed the greatest threat to nationally and internationally important sites in the parts of Oxfordshire and Buckinghamshire affected, so even though the threat to Otmoor has been lifted, the decision is potentially a disastrous one for nature. 

This choice of corridor will make the chance of achieving Highways England’s own objective of  "no net loss" of biodiversity much harder. And this is not just about a new road. The Government's preference for corridor B is clearly based on its alignment with East-West Rail, and the shared potential that offers to support major new settlements and urban growth in this part of the Oxford to Cambridge corridor. New settlements will bring their own challenges – direct land take and loss of locally important habitats, and likely indirect effects including impacts on air quality, water resources, and from increased recreational pressure.

Picture credit: Bittern by Paul Wyeth


Why is it worth fighting for?

We are pleased that the direct threat to Otmoor and the immediate surrounding landscape has been lifted by the Government's decision to exclude corridor sub-option B2 from consideration from this point on. This means the wetland wonderland of Otmoor, which once inspired Lewis Carroll to write "Alice Through the Looking Glass", will be preserved for future generations.

However, numerous other homes for nature are still threatened. Highways England's own assessment of the different corridor options rated Corridors B1 and B2 as red (highly disadvantageous) and Corridor B3 as amber (moderately disadvantageous) for the environment, including impacts on protected sites. We are very disappointed that corridors B1 and B3 are now the only ones still on the table.

The reason for Highways England's assessment are obvious. Beyond Otmoor, the area of Buckinghamshire and Oxfordshire still potentially affected by the Expressway is home to some wonderful homes for nature, including:

  • Two internationally important sites (Special Areas for Conservation or "SACs") south-west of Oxford, known as Cothill Fen SAC and the Oxford Meadows SAC.
  • Over 30 SSSIs, especially large ancient woodland SSSIs in the wider landscape known as Bernwood Forest in Buckinghamshire east of the M40. Many of these sites are precious for their woodland butterflies and bats and include breeding sites for one of the rarest mammals in Britain - Bechstein's bats.
  • The upper Ray Valley, home to nationally rare and declining species like breeding curlews and black hairstreak butterflies. Our partners, Berkshire, Buckinghamshire and Oxfordshire Wildlife Trust (BBOWT), manage an important group of lowland meadows there rich in wild flowers and herbs: a habitat almost gone from much of England. 
  • Right beside the routes of East-West Rail and High Speed 2 lies Calvert Jubilee, another BBOWT-managed site rich in breeding and wintering birds, and butterflies.

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

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

Our position

Otmoor is important to us and as you would expect, we're glad it is safe. But our comments on the corridor options reflected the big picture, looking at the larger landscape areas that are richest in important sites, habitats and species. In spring 2018 we said Corridor B was the worst of the options on offer from the point of view of nature. That hasn’t changed. 

Although the prospect of a major new road across any part of Otmoor has been ruled out by Highways England, many other important homes for nature are still under threat. In a way, that threat is now increased because corridors A and C have now apparently also been excluded – the remaining range of options for where the expressway could go has started to be narrowed down. 

A major highway like this takes a lot of land, so direct loss of habitat could be a major threat. When high road noise levels are introduced to formerly quiet landscapes, research shows the diversity and numbers of breeding birds are often reduced. And because of their width and high traffic volumes and speeds, such roads often form a serious barrier to the movement of many animals. Vehicles kill many animals and for some, this can become a threat to the local populations at large – barn owls and hedgehogs are good examples. Air and water quality can suffer locally as well, with insidious effects on semi-natural habitats like lowland meadows, rivers and streams.

Ahead of the promised consultation on route options we will work on refining and improving our evidence to try to counter any particularly damaging route options that come forward. And we will be highlighting other sections of corridor B we think Highways England should rule out from further consideration sooner rather than later – not just designated sites themselves but buffers and corridors around and between them that help create a coherent ecological network.

The principle of whether there should be an Expressway at all is not something we’ve been invited to comment on, and it's outside Highways England’s remit. But we do think the Department for Transport and the National Infrastructure Commission need to explain very clearly how building this road and all the growth likely to follow it can be compatible with achieving large reductions in greenhouse gas emissions that we need to deliver as a society, to avoid dangerous levels of climate change. This is especially important if the Expressway is to help facilitate large-scale urban growth, as any "headroom" the new road creates in terms of freeing up the strategic and local road network could be rapidly taken up again with extra traffic from new development.

 We are working with allies including the Wildlife Trusts, the National Trust and the Woodland Trust to make sure we're as closely aligned as possible on the most important issues. We are planning to work up a joint vision for the protection and enhancement of nature across the Arc in step with urban growth, and to press the Government and its agencies to adopt as many of the principles as possible.

How you can help

Keep an eye on this page as we will post details of any specific actions you can take here.

Highways England has said it will consult local communities on route options within the preferred corridor in autumn 2019. 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 Chris Grayling MP, who is currently the Secretary of State for Transport.

We are not currently asking local people to support one Expressway route over another because different communities may well have different opinions and concerns about the options, when they come. However, here are a few over-arching things you could consider asking your MP to push for, that would help (below). Refer to our full response under the downloads tab for more detail, and do please take the time to make these points in your own words:

  • That Strategic Environmental Assessment* ("SEA") of the route options should be carried out as a matter of urgent priority, to ensure that less environmentally damaging options are not excluded from further consideration too early in the process;
  • That Highways England should select a preferred route that best avoids and minimises impacts on nature – particularly, nationally and internationally important protected sites;
  • That they should also set themselves an objective of achieving a net gain in biodiversity, not merely one of no net loss as at present. This would be consistent with current national planning and environment policies;
  • That the choice of preferred route must account for likely urban growth scenarios, not just development already in Local Plans. The latter represents only a small part of what the Government intends for the Oxford-Milton Keynes-Cambridge corridor;
  • Finally, you could ask your MP to explain the compatibility of building a major new road and promoting high levels of urban growth with legal obligations to reduce carbon emissions, which are especially needed in the transport sector;

*If you’re confused about SEA and EIA (Environmental Impact Assessment) it's worth knowing that EIA will be done once the 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 would help ensure the best overall choice of solution is made before options are narrowed down and proposals are worked up in full detail. For more information visit the government's guidance page here


  • 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.