The impact of HS2 on London's wildlife

Proposed Colne Valley viaductProposed Colne Valley viaduct

HS2 is a new £56bn railway that will provide a high-speed link between London and Birmingham by 2026. London Wildlife Trust is working to ensure any impact on wildlife by this government-funded project is minimised.

HS2 trainIt was clear from the inception of HS2 that the railway would have significant environmental impacts. London Wildlife Trust expressed deep concerns, early on in the development of the scheme, to HS2 Ltd, the company set up to build and operate the railway.

Since the government confirmed that the railway would be built, we have been working with HS2 Ltd to minimise the impact on wildlife along the route in London.

Enabling and construction works

Since Royal Assent was granted to High Speed 2 in February 2017, work to prepare the ground for the first phase of the railway's construction have begun. Contractors have been appointed to undertake the 'enabling' and main construction works, with each allocated a section of the route. This means significant amounts of land have already begun to change in order to bore the tunnels and construct the operational infrastructure of HS2.

While the Trust has been unable to stop the scheme, we believe our collective action has helped reduce some of the worst impacts of HS2

In London, twin-track tunnels are being bored between Chalk Farm and Old Oak Common, and between Park Royal and West Ruislip. In addition, a 3.6km viaduct is to be built to carry the line from Newyears Green in Hillingdon, over the Colne Valley into Buckinghamshire, before it enters another tunnel through part of the Chilterns. The impacts on the landscape and wildlife are significant, especially between the Chilterns and West Ruislip, even if much of this land will be restored once construction is due to finish in 2025.

At a site east of Harvil Road, south of Harefield, HS2's enabling works contractors, CSjv, are clearing trees and vegetation ahead of essential gas pipeline diversion works required before construction of HS2 can begin. HS2 Ltd and their contractors have completed all necessary ecological surveys and inspections ahead of these clearance works. All works at the site are being undertaken in accordance with the HS2 Environmental Minimum Requirements and the Act of Parliament permitting construction and operations of HS2 Phase One. The gas pipeline works will be undertaken by Cadent Gas under its own permitted development rights and in compliance with HS2's Environmental Minimum Requirements.

With respect to protected species at the site east of Harvil Road, HS2 has confirmed the following:


  • The site has been surveyed and while some signs of badger activity, including latrines (dung pits), were found on site, active badger setts have not been recorded and there are no active setts immediately adjacent to it;
  • Updated surveys will be undertaken as works continue to ensure all works are undertaken in accordance with the legal protection afforded to badgers.


  • As part of HS2's preparation for the start of works, the whole site has been surveyed, using a range of survey methods. No evidence of roosting bats has been found in the area that contractors CSjv are clearing;
  • All precautions are being taken to reduce any risk, including re-inspection by ecologists of trees with moderate or high potential to support roosting bats prior to felling. Should any bat roosts be identified then works in that location will cease and appropriate mitigation and licensing requirements followed;
  • HS2 Ltd will update their surveys as works continue to ensure all works are undertaken in accordance with law.

In addition, HS2 Ltd has confirmed there are no predicted impacts to Newyears Green Covert Ancient Woodland.

HS2 London route map

Our position

London Wildlife Trust has objected to the HS2 route since it was first proposed. However, as the scheme developed we have worked to ensure that as best possible the ecological impacts are minimised and that in time, net gains for biodiversity can be secured. We have worked with our sister Wildlife Trusts to ensure these principles are embedded across the whole route.

While the Trust has been unable to stop the scheme, we believe that our collective action has helped to reduce some of the worst ecological impacts of HS2. We maintain a commitment to pursuing measures to mitigate the impacts on wildlife from the construction of the railway, especially in and around the Colne Valley, although the legal recourse to prevent construction has now been exhausted. 

We acknowledge construction of HS2 will mean the loss of and damage to wildlife


The Trust still faces uncertainty over the future of Frays Farm Meadows, one of our nature reserves in the Colne Valley, which may be affected by a proposed haulage road (to carry out materials from tunnel boring). A decision as to whether this will proceed has still to be made; if it does the Trust has an agreement with the Department for Transport for HS2 Ltd to mitigate and compensate for the damage that may occur and accrue over the period the road is required (last estimated at nine years).

The Trust recognises that many people are angry and upset at the damage they are witnessing where works are underway. We urge these concerns to be allayed to HS2 directly and, if it is felt that legislation is being breached or best practice not carried out on the ground, make sure their local councillors and MPs are also informed. While the Trust has been assured by HS2 Ltd that all the appropriate and legal steps have been undertaken to avoid, reduce or mitigate for the impacts on wildlife, we acknowledge that the construction of HS2 will mean the unavoidable loss of and damage to wildlife habitats especially in the short-term.

We will be working with our sister Wildlife Trusts and others to help scrutinise the development of HS2 as it moves into construction, and highlight specific concerns over – and opportunities to improve – their ecological performance.

How to contact HS2 Ltd

If anyone has concerns over the impact of HS2 construction works on wildlife, we would encourage you to contact the HS2 Helpdesk directly.


Call 08081 434 434

Affected wildlife sites

After initial plans for HS2 suggested that 18 sites of importance for wildlife would be directly impacted, and 39 more indirectly impacted, the Trust argued  that "the current proposed route is likely to have a significant and avoidable impact on the natural environment".

In 2012, in response to views submitted during the first consultation, the government reassessed the route through west London and agreed to place a significant proportion of it in a tunnel. This decision was welcomed by the Trust and meant that several wildlife sites, most notably Perivale Wood, would no longer be affected by HS2. However, the route eventually approved is still likely to impact on 10 wildlife sites in London, not just directly by the main two-track railway but also the enabling and construction works, for example the boring of the tunnels under much of west London and the Chilterns, and the building of a 3.6km viaduct over the Colne Valley.

Sites of Importance for Nature Conservation (SINCs) in London impacted by HS2

  • St James’s Garden, Euston
  • Regent’s Park
  • Chalk Farm Embankment and Adelaide Nature Reserve
  • Wormwood Scrubs Park
  • Mad Field Covert, Railway Mead and the River Pinn
  • West Ruislip Golf Course and Old Priory Meadows
  • Brackenbury Railway Cutting
  • Newyears Green
  • Dew’s Dell, incorporating Dews Farm Sand Pits
  • Mid Colne Valley including Broadwater Lake and Frays Farm Meadows

Colne Valley Regional Park Panel

Many of the concerns relating to the Colne Valley were acknowledged by the High Speed Rail House of Commons’ Select Committee in Parliament during the process of enacting the HS2 Hybrid Bill. This committee backed the creation of a panel to lead the development and implementation of an ‘Additional Mitigation Plan’ to help protect the environment in this region. Any plan agreed will be implemented with a £3m budget set aside by HS2 Ltd specifically for this purpose. This money is in addition to mitigation measures already proposed by HS2.

HS2 Grand Union CanalLondon Wildlife Trust is a member of the Colne Valley Regional Park Panel, established in 2015, which consists of representatives from 15 organisations; including local authorities, government agencies, and environmental groups. Two other Wildlife Trusts – Herts & Middlesex, and Bucks, Berks & Oxfordshire – are represented on the panel. Work on the Additional Mitigation Plan (AMP) started in summer 2016, and it was published in November 2017, with a suite of 14 project proposals.

Seven of the AMP projects are area-specific, including those around Newyears Green, Frays Valley, and Harefield Moor. In addition seven generically-themed projects are aimed at meeting Colne Valley Regional Park objectives including new recreational routes, improving viewpoints, public artworks, better local engagement, and protecting important wildlife in the Valley such as fish, water vole, bats, and birds. For more information email or visit

Frays Farm Meadows

Frays Farm MeadowsThe Trust manages Frays Farm Meadows, a Site of Special Scientific Interest (SSSI) in the Colne Valley. Frays Farm Meadows supports what is probably the largest remaining sedge fen in London; a rare wet grazing meadow that is home to species such as the protected water vole, snipe and slow-worm. In late 2015, HS2 Ltd announced that it intended to build a temporary haulage road that would slice across the northern boundary of the site, destroying habitat and threatening the entire sedge-beds for which the meadows are designated. Other associated impacts would also significantly harm the site and the species that live there.

Although temporary, HS2 say the haulage road would be required for up to nine years. The Trust has campaigned to prevent this road being built, and it is still yet to be confirmed whether it will happen. An additional package of mitigation and compensation measures have been promised – in addition to restoring the land over which the road would run to previous condition – if the road were to proceed.

Broadwater Lake

The HS2 route crosses the Mid-Colne Valley SSSI on a viaduct (pictured, top) bisecting Broadwater Lake Nature Reserve, managed by Herts & Middlesex Wildlife Trust. The 80-hectare site, which lies within London, is renowned nationally for the diversity of breeding wetland birds and the numbers of wintering waterbirds such as gadwall, shoveler and great crested grebe, and summer moult gatherings of tufted duck. The original HS2 mitigation does not go far enough to reduce the impact of the viaduct, hence the proposals to include additional works, including screening, in the Colne Valley AMP.

Hedgehogs in Regent’s Park

HedgehogIn Regent’s Park, HS2 is threatening to eradicate an area known to be a hedgehog hotspot. The car park in the Outer Circle of the park and its surrounding green areas are proposed to be used as a HGV holding area. This is the only inner London greenspace known to support a breeding population of hedgehogs, currently regarded as “isolated and extremely vulnerable” during a Park survey in 2014. The hedgehog population in the car park area is thought to constitute 27 per cent of the hedgehogs now living in central London (from current data).

The Zoological Society of London and The Royal Parks are working together to try and ensure the impacts of the HS2 compound at this site are minimised.

Ecology Review Group

The Wildlife Trusts, which London Wildlife Trust is part of, are represented on HS2’s Ecology Review Group. This group is working on a package of biodiversity measures that will partly mitigate the impact of HS2. A report from the group, called ‘No Net Loss’, is due to be published later in 2017.