Oxford to Cambridge Expressway

Oxford to Cambridge Expressway

Bernwood meadows by Rhea Draguisky

The Oxford to Cambridge Expressway: a threat to wildlife.

Stunning wildflower meadows, ancient woodlands, hedgerows alive with birds and butterflies, and gentle undulating ridge and furrow fields which have survived from the Middle Ages – these are all under threat from the proposed Oxford to Cambridge Expressway.


18 March 2021

We are delighted that the Secretary of State for Transport, Grant Shapps MP, has today cancelled the OxCam Expressway. We have opposed the Expressway from the very beginning and were engaged in a legal battle in the High Court with the Government over its plans. Whilst we will take a brief moment to welcome this decision, we cannot turn our attention away from the other threats to our area. We need to ensure that other road building projects do not amount to the Expressway in all but name. Plans for “improvements” to the A34 west of Oxford could have a devastating impact on precious habitats and designated sites for nature, so the pressures on wildlife continue.

Plans for the OxCam Expressway should never have got this far. Lessons need to be learnt going forward so the mistakes in failing to properly look at the environmental impacts of such proposals up front are not repeated.

Despite this cancellation, it is clear that a huge level of development is still planned for the Oxford to Cambridge Arc. It is clear that some level of development is still planned in the Oxford to Cambridge area. In the budget, released 11 Mar 2020, the associated housing development in the OxCam Growth Arc was mentioned. We are continuing our advocacy work, insisting that decision makers plan developments that put nature first. While we appreciate that housing need must be met, in this time of climate and ecological emergency development must help restore nature, not destroy it.

The proposals for this Oxford to Cambridge Growth Arc, as they are currently being planned and delivered, simply won't work. In June 2020 BBOWT, along with the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire (WTBCN), the RSPB, and the Woodland Trust, published Nature's Arc, a set of principles for protecting and restoring nature and tackling climate change if any large scale developments get the go-ahead in the Oxford to Cambridge area. If these principles are not met, development should not go ahead and we will continue to campaign against damaging developments across the Arc.

You can read more below about the background of the Ox Cam Expressway and Growth Arc and our campaign against it.


We fundamentally question whether the area can support one million new homes without causing untold damage to wildlife. We also question whether an Expressway can be justified when our natural environment is already straining under the pressures caused by people, without an additional concrete corridor covering vast swathes of our countryside adding to such stresses.

Legal dispute with government

A dual carriageway road and up to one million new homes could threaten scores of wildlife sites between the two cities. Between late 2018 and 2019, the Berks, Bucks and Oxon Wildlife Trust were engaged in a legal battle with the government. The foundation of our case was that the government failed to assess the environmental impact of its plans before choosing its preferred  corridor of land for the development. In June, this reached the stage of judicial review in the High Court. In July, the High Court ruled against us. We have decided not to appeal this decision - the costs would be too high, and our legal advisors have advised against it.

Timeline of our legal challenge:

We will keep this page updated with our next steps. We will challenge Government throughout the planning process where we see failings in their actions. We will continue to champion and speak up for wildlife at every stage of the process.

Our legal challenge has taken place against the backdrop of work beginning on the High Speed 2 railway. There were no strategic environmental assessments for this project either, and the clearance of sites prior to construction work has resulted in destruction of wildlife habitats. We raised our concerns about HS2 from the beginning, and are dealing with the consequences of the government’s failure right now at our Calvert Jubilee nature reserve.

We will continue to speak up for the environment and wildlife. We will not let the government off the hook and allow this project to devastate our natural environment.

Find the latest news about our Ox-Cam Expressway legal challenge


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Short-eared owl hunting by Ben Hall/2020VISION

Highways England failed to commission a Strategic Environmental Assessment (SEA) or a Habitats Regulation Assessment (HRA) as part of the process of selecting their preferred corridor of land. These are required under European Law for schemes that impact on the environment such as this. This means the true environmental impact has not been properly considered.

The corridor of land that the government has chosen is very broad and the precise location of the Expressway and housing is yet to be decided. However, we do know that this corridor includes many protected areas for wildlife. There are three Special Areas of Conservation (SACs) which are strictly protected sites under the EC Habitats Directive, and roughly 50 Sites of Special Scientific Interest.  There are also roughly 280 Local Wildlife Sites, which are some of our most valuable wildlife areas, and which are identified and selected locally using scientifically-determined criteria and surveys. To avoid all of these sites the Expressway would have to be so convoluted it would fail to live up to its name.

If it were to go ahead, we do not know whether the Expressway will take a clockwise or anti-clockwise route around Oxford before heading north east to Cambridge. However, if the A34 is widened west of Oxford the increase in traffic and pollution could affect sensitive areas such as Oxford Meadows, Cothill Fen and Wytham Woods. An alternative route around the south and east of Oxford would potentially impact on important areas for nature conservation including Bagley Wood, Sandford Brake, Brasenose Wood and Shotover Hill.

Bernwood Meadows

Bernwood Meadows by Tim Read

The area east of Oxford is characterised by a mosaic of ancient woodlands, species-rich grassland, open water, scrub and hedgerows, which form part of the former Royal Hunting Forest of Bernwood. It is one of the most undisturbed and wildlife-rich areas of Buckinghamshire. The Upper Ray Valley would be at risk, along with ancient woodlands in the vicinity of Calvert, including Finemere Wood nature reserve.

Why does it matter?

The complex of designated sites and nature reserves in the areas of Cothill Fen, Oxford Meadows, the Otmoor Basin, the Upper Ray Valley and Bernwood Forest contain rare habitats and wildlife, including:

  • Ancient floodplain flower-rich meadows of a type so rare that only 1500 hectares remain in England

  • Ancient woodlands, including those in the Bernwood Forest that support the Bechstein’s bat, one of Britain’s rarest mammals
  • Rare fens, of a habitat type so rare that only 19 hectares remain in England 
  • Floodplain grazing marsh supporting some of the best remaining populations in lowland England of rare and declining waders such as curlew, lapwing, redshank and snipe
  • Ancient hedgerow networks that are the UK stronghold for the rare black and brown hairstreak butterflies.

You can read our FAQs here.  

For more information about the potential impact of the Expressway on wildlife, you can download the Wildlife Trust's consultation response, and the Executive Summary of the response from the Berks, Bucks & Oxon Wildlife Trust, by clicking the links below.

photo of curlew

Curlew by Damian Waters / Drumimages.co.uk

Further reading

Response from the Wildlife Trusts

Read the Wildlife Trusts' full response to the Oxford to Cambridge Expressway Consultation. 

Read the report
bee on scabious

Bee on scabious by Kieron Huston

Further reading

BBOWT Executive Summary

Read BBOWT's Executive Summary of The Wildlife Trusts’ Consultation Response.

Read the summary

Wildlife in this country is in serious trouble. Many species are in steep decline. The government has committed to leave the environment in a better state than they found it, but it is unclear how the Expressway and its potential impact on protected habitats is compatible with this ambition.

On Budget Day, at the end of October, the Chancellor of the Exchequer gave his support for the National Infrastructure Commission’s recommendation to build up to one million new homes in the vicinity of the Expressway. To get a sense of the scale of this proposal, we know that the current population of Oxfordshire, Buckinghamshire and Milton Keynes (areas where BBOWT operates) is very roughly 1.5 million people, and the average number of people per home is 2.45. That means there are currently more than 600,000 homes.

Even if only half the new homes are built across Oxfordshire, Buckinghamshire and Milton Keynes (and the other half in Bedfordshire, Cambridgeshire and Northamptonshire) it will still represent a near doubling of homes.

We have yet to see evidence that 1,000,000 homes and a new Expressway can be delivered in a sustainable way without inflicting untold damage on our natural environment. One key concern we have is that our broken planning system enables a piecemeal approach to be taken and connected building projects to be carved up to mask their true environmental impact. The growth arc needs to be looked at in its totality, rather than the Expressway being considered in isolation and the 1,000,000 homes being looked at as a huge number of individual housing developments. Water stress, transport infrastructure, housing, compatibility with climate obligations and green infrastructure all need to be considered together when reviewing the sustainability and deliverability of the growth arc. 

Without a Strategic Environmental Assessment of the Expressway and housing ambitions combined, we don’t know what damage will be done to the local environment. The approach of accepting the creation of an Expressway within an already selected corridor and the building of 1,000,000 new homes, and then later looking at the environmental impacts, is entirely backwards and treats the environment as an afterthought. The government must stop any progress on the growth arc until it has carried out all necessary assessments to determine the true environmental impacts of its proposals.

photo of a snipe

A snipe, one of the rare wading birds whose habitat the Expressway corridors threaten © Margaret Holland

What are BBOWT doing?

  • In April 2018 The Wildlife Trusts made a submission to a Highways England closed consultation about the Expressway. You can read that response here. We warned that Corridor B would have the worst impact on wildlife of the three corridors that were then being considered.
  • On 12 April 2018 we wrote to the Secretary of State for Transport, the Rt Hon Chris Grayling MP, about the lack of a Strategic Environmental Assessment (SEA) when selecting the corridor for the Expressway (read our letter).
  • We responded to the government's announcement on 12 September that it had chosen Corridors B1 and B3 - and rejected Corridors A, B2 and C.
  • We launched our legal challenge to the government and Highways England on 27 September with a 'pre-action protocol letter'
  • In November we launched our online fundraiser to cover legal fees.
  • In November we issued a claim against the government because we were dissatisfied with the response to our 'pre-action protocol letter'.
  • In mid-January, the court refused permission for our claim against the government. We appealed this decision and asked for an oral hearing.
  • In mid-February, the permission hearing was held and the initial decision overturned. The appeal was successful, which means we can bring our claim against the government to the court for a full hearing. 
  • In mid-June we returned to the High Court for our judicial review hearing. Judgement was reserved, meaning we did not know the verdict immediately.
  • In July, the High Court ruled against us. 
  • We decided against appealing this decision - the costs would be too high, and our legal advisors have advised against it.

We will challenge Government throughout the planning process where we see failings in their actions. We will continue to champion and speak up for wildlife at every stage of the process.

Find the latest news about our Ox-Cam Expressway legal challenge

Frequently asked questions

What is this all about?

On 12 September 2018, the Department for Transport announced its chosen geographical location for an Oxford to Cambridge Expressway – a major road linking the two cities – and associated housing development that will be built near to the Expressway. The government refers to this as the ‘Oxford to Cambridge Growth Arc’. 

The Department for Transport had three broad ‘Corridors’ between Oxford and Milton Keynes to choose from, and it chose Corridor B.

In April 2018, BBOWT submitted a document to a Highways Agency consultation about this project, and we clearly said that all three Corridor options would have a serious impact on wildlife, but that Corridor B was the worst of the three options. We told them then that Corridor B should be discounted due to the exceptional impact it could have on wildlife. 

We also pressed the Government to undertake a Strategic Environmental Assessment (to assess the environmental and sustainability impacts), which we believe should be done for a project of this nature and scale, and which may be required in order to comply with EU legislation, but they failed to do this.

What was BBOWT's response to the government's announcement of the chosen corridor?

You can read what we said on 12 September when the Department for Transport announced that it had chosen Corridor B here.

Responding to the announcement, our CEO, Estelle Bailey, said, ‘In our opinion Corridor B is the worst of the three options. We told Highways England that the potential impact on biodiversity of Corridor B is so serious that the route should have been discounted entirely. The only way to avoid exceptionally serious impacts on biodiversity would be to develop a road route that is so convoluted that it would fail to qualify as an expressway. Our most serious concerns are for the designated sites and nature reserves in Cothill Fen, Oxford Meadows, the Otmoor Basin, Upper Ray Valley and Bernwood Forest.’

Why is BBOWT so worried about the impact of the Expressway/Growth Arc?

The scale of the project

We are concerned not just about the Expressway but about the extraordinary scale of the government’s proposed house building, which this road is proposed to enable. A 2017 report by the National Infrastructure Commission stated that house building needs to double in the Oxford-Milton Keynes-Cambridge ‘arc’ in order to deliver up to one million new homes by 2050. 

The choice of Corridor B

As outlined in our consultation response from March 2018, Corridor B has shown to be the one that has the greatest adverse effects on designated sites and priority habitats. Despite this Corridor B has been chosen as the preferred corridor.

It is important to note that Highways England divided Corridor B into three sub-corridors called B1, B2 and B3. When they made the announcement that Corridor B was the preferred corridor, they discounted sub-corridor option B2.

We have yet to analyse in detail what the omission of sub-corridor B2 means with regard to direct impacts on designated sites but an initial review suggests that Corridor B remains the worst corridor option compared to Corridors A and C.

In this context it is also important to note that we are not only concerned about the direct effects the Expressway and associated development will have on designated sites and wildlife but also about potential indirect impacts (eg. hydrological changes, air pollution, recreational pressure), which we believe will reach beyond the chosen corridor.

As outlined in our consultation response earlier this year, our most serious concerns are for the designated sites and nature reserves at Little Wittenham, in Cothill Fen (including Dry Sanford Pit and Lashford Lane), Oxford Meadows (including Oxey and Pixey Meads), the Otmoor Basin, Upper Ray Valley (including Gallows Bridge Farm and Meadow Farm), the Bernwood Forest (including Finemere Wood and Rushbeds Wood) and Calvert Jubilee.

The ‘Common corridor’ South of Oxford is up to 20km wide and has the potential to significantly impact on designated sites near Blewbury and Little Wittenham/Dorchester, the latter of which also includes a nature reserve.

Currently it is not clear whether the Expressway will circumvent Oxford to the West or the South. If it goes around the West the increase in traffic and pollution, and potential changes in hydrology, could affect sensitive areas such as the Oxford Meadows, Cothill Fen and Wytham Woods. If it goes around the South it has the potential to impact on areas of nature conservation interest south and southeast of Oxford - although the omission of sub-corridor B2 assists in reducing direct impacts on some important designated sites in this area. 

In Buckinghamshire, it will affect the former Royal Hunting Forest of Bernwood and the Upper Ray Valley, and this is also where the routes around Oxford will converge. The Forest of Bernwood is characterised by a mosaic of ancient woodlands, species-rich grassland, open water, scrub and hedgerows. It is one of the most undisturbed and wildlife-rich areas of Buckinghamshire. 

The Upper Ray Valley, described as one of the most important areas of lowland meadow and grazing marsh in south east England, and where rare waders breed, is at risk. Also at risk are the ancient woodlands in the vicinity of Calvert, including Finemere Wood, home to one of the few known populations of the rare Bechstein’s bat in Britain, and the old hedgerows that support rare black and brown hairstreak butterflies. New towns or even a city might be proposed in this area which would have devastating effects on habitats and wildlife.

Is BBOWT opposed to the Expressway/Growth Arc?

We are not opposed to development in principle but we are completely opposed to the process by which the corridor has been selected and believe that the rationale provided for the Expressway has not been sufficient.  We are therefore calling for a Strategic Environmental Assessment (SEA), which would result in the government needing to justify an Expressway balancing the needs of society, economy and the environment.  

It is because of the failure to follow due process and to conduct an SEA that BBOWT has launched a legal challenge against the government. We will be prepared to go to Judicial Review if necessary. 

Where are people supposed to live if you oppose house building?

While we recognise the need for new housing in our area, we simply cannot accept an approach that fails to consider our precious local places and local wildlife. The area covered by ‘Corridor B’ is home to some wonderful wildlife and wild places (see above). BBOWT works closely with local authorities to try and ensure that new houses are built in places that will have a minimal impact on local wildlife. 

Where exactly will the Expressway be built?

All we know at the moment is that it will be in Corridor B1 or B3 (sub-corridors within Corridor B). The Department for Transport ruled out Corridor B2, which runs along the middle of Corridor B, when it made its announcement on 12 September.

Highways England’s website says, ‘We have rejected Corridor B2, whilst it offers similar benefits at a similar predicted cost to B3, the environmental impacts around the Horspath and Wheatley areas are substantially more difficult to overcome. There are also a number of significant constraints as the corridor heads north toward Bicester, including Otmoor Nature Reserve’. For more information, see the Highways England Oxford to Cambridge Corridor Overview Booklet.

The government says there will be a public consultation in autumn 2019 about the details of the route.

What is the timescale for building the Expressway?

According to Highways England’s website there will be a public consultation in autumn 2019 about route options within the selected corridor, and an announcement about the preferred route in 2020. It also states that construction will begin in 2025, and construction will be completed in 2030.

Why isn’t BBOWT a member of the No to the Expressway Alliance?

We share some of the concerns of the Alliance but not necessarily all of them, so we believe it is better to retain an independent voice on the matter.  We are focusing our efforts on the legal challenge and specifically the impact on wildlife.

Where can I find out more?

We will keep this webpage updated whenever there is news on our response to the Expressway. You can also read our news here.

You can also visit Highways England's website to read more about the project and process.

What can I do to help?

In November, we launched a fundraising campaign to help cover our legal costs. We are extremely grateful to everyone who donated. Thanks to you, we were able to speak up for our threatened wildlife. Our fundraising appeal for the Ox-Cam Expressway is now closed, but if you would like to donate to BBOWT's work speaking up for wildlife, you can do so below.

Donate to BBOWT

We are so encouraged and moved by how many people have asked us this question. Thank you! 


Last updated June 2020

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