Flawed HS2 Ltd calculations and mapping include:

Significant mapping errors and poor digitisation. Numerous field trees, ponds, other waterbodies and watercourses (ditches and drains) are unaccounted for in the baseline mapping and are therefore excluded from the assessments.

Watercourses: As a result of HS2 Ltd’s flawed No Net Loss metric, there’s no differentiation between rivers, or streams. Any damage caused during the construction of the scheme is essentially unaccounted for and HS2 Ltd is only accounting for the overall loss in length, rather than the nature value of a specific river or stream.

Woodland: HS2 Ltd’s No Net Loss metric overvalues the woodland that the company will create to compensate for the loss of existing species-rich woods by at least half and overvalues grassland it plans to create to compensate for the loss of existing species-rich grassland by at least a third, compared to the current industry standard.

Hedgerows: Many hedgerows have been significantly undervalued in baseline calculations, and overvalued in the post-construction assessments, particularly compared to the current industry standard.

HS2 Ltd promised that nature would not lose out when much-loved natural areas and important habitats were destroyed to make way for construction of the high-speed rail line. It made a commitment to No Net Loss of biodiversity for replaceable habitats along Phase 1 and 2a of the route, and a net gain for biodiversity along Phase 2b.

Compensating for nature losses relies on accurate baseline assessments of the value of wildlife habitats along the route – for example, by looking to see how species-rich the grasslands are or how diverse woodlands are in terms of the mix of native tree species and complexity of woodland structure, the quality of the understorey and woodland floor plants.

Taking a conservative approach to the data, the report highlights alarming errors in HS2 Ltd’s calculations and mapping, indicative of a large-scale problem, which calls into question the adequacy of all HS2 Ltd’s nature restoration and compensation plans.

Our Phase 1 calculations show that there will be at least 17% less nature present after construction than there was before building started. HS2 Ltd’s figures say there will only be a 2.6% nature loss.

For Phase 2a, we found that there will be at least 42% less nature present after construction than there was before building started. HS2 Ltd’s figures say there will only be a 17.01% nature loss.

As things stand, HS2 Ltd will not compensate sufficiently for the damage likely to be caused by Phases 1 and 2a of the scheme. If HS2 Ltd continues to use the same metric, it will not come close to delivering a Net Gain for Biodiversity for Phase 2b.

A comparison of No Net Loss calculations is as follows:

Phase 1 (2021 scheme), Cheshire Wildlife Trust’s assessment indicates a minimum net loss of 4,367 NNL units (17.36% loss of the pre-construction biodiversity value in NNL Units). This compares to a net loss of 555 NNL units (2.60% loss of the pre-construction biodiversity value in NNL units), as calculated by HS2 Ltd.

For Phase 2a, Cheshire Wildlife Trust’s assessment indicates a minimum net loss of 4,891 NNL units (42.80% loss of the pre-construction biodiversity value in NNL Units). This compares to a net loss of 1,342 NNL units (17.01% loss of the pre-construction biodiversity value in NNL units), as calculated by HS2 Ltd.

The Wildlife Trusts' recommendations in full:

1. HS2 Ltd should re-map existing habitats along Phases 1 and 2a, correcting mapping errors, applying the correct nature values to habitats, and ensuring no habitats are excluded.

2. HS2 Ltd should recalculate the total impacts to nature, by using an up-to-date and proven methodology, such as one directly comparable to the government’s current Biodiversity Metric 3.1. If changes to the methodology are made these should be transparent and evidence-based. It is critical that HS2 Ltd ensures all data is made publicly available at the point the figures are released to facilitate transparency and enable independent scrutiny.

3. The Government should respond swiftly to our findings, while there is still time to change the scheme’s design and delivery to limit the adverse impacts and enhance biodiversity in a way that is commensurate with the scale of the damage – by achieving a minimum 10% biodiversity net gain for replaceable habitats for each phase of the scheme.

4. HS2 Ltd should immediately pause all construction and enabling works and halt the passage of the Phase 2b Hybrid Bill whilst these new findings are assessed by the Government.

The Wildlife Trusts have published an open letter to Secretary of State for Transport, Rt Hon Mark Harper, and Secretary of State for the Environment, Rt Hon Thérèse Coffey MP, urging them to work together to address the new evidence about biodiversity loss calculation errors by HS2 Ltd and asking for an immediate pause on construction.

No Net Loss: To deliver No Net Loss (NNL), the HS2 high speed rail scheme would have to balance damage to biodiversity caused by its construction with at least equivalent gains.  (Any damage to irreplaceable ancient woodland is not part of No Net Loss calculations and compensated for separately.)

Biodiversity Net Gain: (BNG) means the natural environment should be left in a measurably better state than it was beforehand. HS2’s BNG commitments are voluntary, and not legislated. 10% BNG will eventually be mandatory for development which goes through the usual Local Authority planning route (housing and commercial development). It is not yet a legal requirement, although BNG is in the Environment Act there is a transition period before it takes effect and becomes a legal requirement. For Nationally Significant Infrastructure Projects (NSIPS) it is likely to become a legal requirement in 2025.

Analysis of No Net Loss, HS2 phases 1 and 2a: To replicate HS2 Ltd's approach as closely as possible, Cheshire Wildlife Trust recalculated the impacts to biodiversity caused by the construction of Phases 1 and 2a of the scheme using HS2 Ltd’s own NNL biodiversity units. HS2 Ltd’s own No Net Loss biodiversity units measure the value of different habitats according to their size and how nature-rich they are. For the post-construction assessment (i.e., assessment of nature once the scheme is built) the only amendments were to correct obvious mistakes made by HS2 Ltd.

Using HS2 Ltd’s own data where available and additional information to show the type and quality of each habitat, Cheshire Wildlife Trust interrogated HS2 Ltd’s mapping and assessment of existing nature along the route and found a catalogue of errors. For example, within HS2 Ltd’s pre-construction footprint, many habitats such as field trees, ponds, watercourses and hedgerows are misrepresented, undervalued or in some cases not accounted for at all. This means that HS2 Ltd needs to provide far more nature compensation than it thinks is necessary, due to its serious underestimation on the impacts to nature.  Much of HS2 Ltd’s data is hard to access. This, combined with HS2 Ltd’s own inadequate methodology means Cheshire Wildlife Trust’s figures in this report are almost certainly an underestimate and are indicative of the scale of the issues, rather than definitive. They are a warning of the likely errors and inaccuracies built into HS2 Ltd's current approach. Comparing the assessments carried out by HS2 Ltd with those carried out by Cheshire Wildlife Trust, it is clear that HS2 Ltd’s calculations result in some glaringly inaccurate values for the loss of biodiversity resulting from both Phase 1 and Phase 2a.

HS2 Ltd’s Metric:

HS2 Ltd has developed its own distinct, and modified ‘accounting tool’ for nature, based on a 2012 Defra pilot metric. HS2 Ltd has been very clear that it is not using these calculations to inform the provision or the appropriateness of compensatory habitat. The like for like or better rule of the current up-to-date government metric is not being applied. The result is that, for example, many complex and well-developed semi-natural woodland ecosystems will be replaced with simplistic homogenous habitats of little value to wildlife.

In 2016 Natural England reported ‘In light of the wide-ranging issues that using the HS2 NNL metric as an accounting tool has presented, it is recommended that for Phase 2 of the scheme a metric is applied for biodiversity offsetting purposes, i.e., a tool to inform compensation provision. It is considered that this would be beneficial for the natural environment, for reporting purposes and for HS2 Ltd.’

The HS2 NNL calculations demonstrate that HS2 Ltd have not taken on board these particular recommendations from Natural England and the NNL metric is still not being used to inform the type of compensation required.

Natural England, 2016, Review of the High Speed 2 No Net Loss in Biodiversity Metric.. 

HS2 and The Wildlife Trusts:

The Wildlife Trusts support the need for better and more sustainable public transport, but nature, which is a vital ally in the fight against the climate crisis, must not pay the price.  For more than a decade The Wildlife Trusts have highlighted the impacts on nature of the HS2 route, the scheme’s design and the UK Government’s approach to its delivery. In 2014, The Wildlife Trusts set out a ‘Greener Vision’ offering ideas for large-scale nature restoration along the proposed route.

In January 2020, The Wildlife Trusts’ report: What’s the Damage? Why HS2 will cost nature too much highlighted the impacts for wildlife and wild places, increased habitat fragmentation and the possibility of local area extinction of endangered species. It was supported by National Trust, RSPB and Woodland Trust.

HS2 claims it is “the UK’s flagship transport levelling up project ‘Levelling up’ needs to ensure nature, with all the wellbeing benefits it brings to communities living close to the route, does not lose out.

In 2022 Cheshire Wildlife Trust, as the leading local environmental NGO in the area impacted by HS2 Phase 2b, submitted its petition to the High Speed Rail (Crewe-Manchester) Bill. Amongst other objections this cited “a reprehensible lack of transparency regarding how HS2 Ltd has assessed the likely impacts to the natural environment”.