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HS2 Phase 2b Environmental Statement Management through progressive assurance

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The Phase 2b Environmental Statement (ES) was one of the largest produced in the UK in recent years. The ES required inputs from a diverse range of organisations across the supply chain and within HS2 Ltd. In order to facilitate the production of a robust, consistent and proportionate ES compliant with Parliamentary Standing orders, a system of ‘progressive assurance’ and collaborative working was set up by the HS2 Phase 2b Central Environment team together with the Environmental Overview Consultant Arup. This approach allowed the majority of the ES deliverables to be monitored for quality, consistency and adherence to the ES programme. Progressive assurance and collaborative working was achieved through flexible and bespoke cross team collaborative working; ‘live’ reports for cross team authoring, progressive reviewing and assuring; and a toolkit to manage and monitor activity, risk and progress.

The progressive assurance approach led to an improved quality of technically compliant reports and mapping for the Phase 2b ES within a constrained programme. Whilst some of the individual assurance and certification processes may not be necessarily novel on their own, the combination of all of these tools and the collaborative way of working to implement HS2 Ltd.’s ‘three-lines of defence’[1] assurance process meant that HS2 Ltd had a high level of confidence in the robustness of the ES which reduced the risk associated with non-compliance with Standing Orders for a hybrid Bill submission. This innovative approach of progressive assurance and collaborative working, and the tools created to facilitate it, is the learning legacy from the Phase 2b ES that could be implemented on other large-scale projects including other disciplines beyond environmental assessment.


Background and industry context

The HS2 Phase 2b hybrid Bill (hB) was deposited to parliament in January 2022 and included one of the UK’s largest Environmental Statement (ES) and Equalities Impact Assessment (EQIA) in recent years. The Phase 2b ES and EQIA were developed over five years, and the ES included five Volumes, a Non-Technical Summary (NTS), Background Information and Data (BID) reports and maps.

An Environmental statement provides an overview of the Proposed Scheme and the environmental impact assessment process. The purpose of the ES is to help Parliament to make decisions about the project based on a full understanding of any effects, positive or negative, that it may have on the environment. The ES also enables anyone with an interest in the project, including the general public, to understand how it will affect them and to express their views on the effects of the project[2]

The documents submitted to Parliament needed to be compliant with Parliamentary Standing Orders[3] which are exacting on the quality requirements for an ES. This required the maps and reports to be consistent across the Volumes, topics and route sections, the documents had to read as if they have been written by ‘one pen’. This was very challenging due to the scale and programme of the ES and the numerous specialist teams involved from a diverse range of organisations.

The ES programme was designed around a series of three ‘formal review’ drafts and the requirement to have a ‘three-lines of defence’[1] assurance process. At each draft new information was introduced for review and the objective was to agree and as far as possible finalise areas of reporting so that it did not need to be revisited at later drafts. The design was being developed in parallel with updates for each formal review.

Figure 1 shows the overall structure of the ES for Phase 2b. The largest component (75%) of the ES was Volume 5, the technical appendices and the BID reports (255 technical reports amounting to around 10,500 pages), and associated maps (around 3,000 map sheets). These technical appendices and maps were where the baseline information and assessment findings were reported. It would have been impossible, within the constraints of the programme, for all reviewers to check all the information in these technical appendices at each formal review, the formal reviews were designed to principally focus on the overarching Volumes (Volumes 1- 4) and the NTS.

Diagram showing the structure of the environmental statement
Figure 1 – Structure of the Environmental Statement

To enable formal reviews to focus on the NTS and the main Volumes, there needed to be confidence that the technical information in the appendices and BID that underpinned these Volumes was correct. Rather than extend the formal review stages or introduce additional transactional reviews an innovative process of collaborative working and technical progressive assurance was developed and implemented.


Progressive assurance is a process of bringing forward elements of assurance to allow them to take place in a more collaborative and less transactional way ahead of formal reviews stages. This approach placed an emphasis on self-assurance and strived to achieve deliverables being ‘right first time’. For the Phase 2b ES there were many teams involved in the production of the deliverables therefore the progressive assurance approach required a high degree of collaboration and coordination between all the relevant parties.

Figures 2 and 3 provide an illustration of progressive assurance versus a more traditional approach of ES report submission and review in the context of HS2 Phase 2b. As illustrated, the key driver(s) of moving away from the traditional model were:

  • to avoid the risks and challenges posed by undertaking all assurance across the full ES in short defined periods (the formal reviews)
  • to ensure that technical reviewers had adequate time to develop a deeper understanding of the work as it emerged
  • to be involved in understanding the challenges of the assessment
  • to provide direction on the assessment and reporting outputs.

The progressive assurance model brought forward as much of the topic-based technical assurance ahead of the formal review periods as possible via a combination of planned meetings and hosting ‘live’ reports on a central SharePoint location. This allowed technical assurance to take place as soon as technical content was available (e.g. baseline data is reviewed as soon as its drafted, followed at a later stage by the assessment work, and later for mitigation development). Each report was accompanied by a Cover Sheet which was used by all parties to record activity in the live reports and flag any limitations, caveats and risks that were identified during that activity.

Chart of traditional assurance model
Figure 2 – Traditional assurance model

Chart of  Progressive assurance model
Figure 3 – Progressive assurance model

The approach ensured that the development and assurance of the ES topic technical work and the preparation of the appendices and BID reports was a continuous, fluid process spread across the duration of the ES delivery programme. This achieved the aim of avoiding finalising and assuring all ES Volumes, BID, maps and the NTS in the key latter part of the programme, therefore reducing the risk of not meeting the programme as well as improving the quality and robustness of the ES reporting overall. The ongoing visibility of the ES topic technical appendices gave HS2 Ltd greater confidence in the team’s ability to meet the programme, and key challenges were identified early, allowing them to be managed appropriately.

To support progressive assurance, the following tools and approaches were developed and used:

  • Progressive Assurance Plan and briefings – a Progressive Assurance Plan and briefing packs were prepared to explain and illustrate what the programme challenge meant to the project and why there was a need to plan differently for the review and assurance of the large number of Volume 5 and BID reports.
  • Progressive Working and Assurance Plans (PWAP) – these were prepared at the start by each environmental topic team. The PWAP set out who and how that topic team, (across the three parties involved), would work together over the duration of the programme and how the drafting and ‘three-lines of defence’[1] assurance would be implemented to ensure a robust product would be produced and signed-off on programme. The PWAP sets out what that topic’s key issues and challenges were, what their data gathering cut-off points and design freeze dates where, what stakeholder consultation was taking place and cross-volume and cross-topic dependencies. Each topic’s PWAP was different and the teams established their own working arrangements for collaborative working, progressive assurance and co-working meetings to suit their topic’s requirements and programme. The PWAP was held ‘live’ on the SharePoint platform and was updated routinely specifically setting out the key issues and challenges and the actions identified. Meeting minutes were saved on SharePoint for all to access. The PWAP and meeting minutes were used by wider teams across HS2 Ltd and all of the contributing supply chain teams to gain greater visibility of the work progress and challenges, and to support risk management.
  • Live working on SharePoint – all the Volume 5 and BID reports were kept live on the SharePoint platform from their first draft through to print preparation and PDFing. All team members could view each report at any time. This allowed for the development of the reports to be monitored and assured continuously on a real time basis rather than a slow transactional approach between parties. Multiple people could be in a report at any one time, live screen shares aided quick discussion and issue resolution and report backups are automated and continuous.
  • Cover Sheets – each of the Volume 5 and BID reports had a Cover Sheet in an Excel workbook. This was used to record real time key information on the report’s status including the owner, checker and approver and also to record in a log all key activity by all parties involved the live reports (from authoring, to assurance, reviews, editing and sign-offs). Parties could indicate on the Cover Sheet if they felt the report was ‘on track’ or ‘at risk’ (risk being to quality or programme). The Cover Sheet was used to inform final ES sign-off and certification by HS2 Ltd.
  • Progressive Assurance Protocol – a protocol was prepared setting out the ‘rules of engagement’ with the live reports and Cover Sheets on SharePoint to ensure editorial control was retained by the report owners and all parties knew where to find the reports and Cover Sheets and how engage with them.
  • The Integrated Assurance Programme (IAP) – the IAP was the detailed programme per topic and per report setting out when each would be drafted, checked, reviewed, assured etc. by each party. This sat under the Day to Day programme. The finalisation of the Volume 5 and BID reports required numerous cross checking against other similar reports, other topic reports, mapping, other Volumes as well as the Style Guide all of which had their own programme for finalisation; the IAP ensured that reviewers understood when each report was ready for each type of review and at what stage in its development it was at.
  • Power BI tool – Power BI was used to read from the Cover Sheets and was used to track progress in real time through drafting, checking, reviewing, assuring and sign-offs (codes where used for all these steps). It could also indicate if reports had been raised ‘at risk’.
  • Production Tracker– this was closely aligned to the IAP and listed out each report, its name, code, owner and recorded the production status of each of the Volume 5 and BID reports as they were signed-off and checked by the HS2 Ltd Production Team for printing. It was also used to manage late edits post technical sign-off.
  • Dashboard – a Volume 5 and BID dashboard was circulated around the team weekly giving a summary update on the reports and their progress using data from Power BI, the IAP and the Production Tracker.

All of the above tools and processes enabled the teams to work collaboratively in an ongoing live real time manner developing and assuring the Volume 5 and BID reports progressively from their early drafts in line with their PWAP plan. This activity was focused on the windows of time between the formal review periods allowing the focus at the formal reviews and the Page Turns to be on the main ES Volumes (1-4) and on key issues identified by the topic teams.

The evidence of progressive assurance lies in the PWAP, the co-working meeting minutes, the Cover Sheets and the live reports which support and facilitate final approval and sign-off of the Volume 5 and BID reports by HS2 Ltd.

Outcomes and learning

Progressive assurance allowed the team to make significant efficiencies within the ES review process, reducing the overall ES programme and enabling more time for technical assessment by the topic teams. This resulted in increased early understanding of issues, increased opportunity for the technical teams to propose and agree mitigation, greater confidence in the production of a good quality, compliant ES and reduced risk to the parliamentary process.

Cover Sheets and live working allowed the reports to be monitored continuously and their status ascertained by the technical topic leads without the formal submission of the actual reports themselves (and without the additional pressures on the authoring team of assuring work internally for formal review, uploading documents, reviewing comments, incorporating comments and edits back in to the master reports etc.). This led to a better and more timely understanding of the technical work and improved quality of all the deliverables throughout the ES programme.

The PWAP, IAP and the Production Tracker allowed live and real time tracking of report status and risks providing an early warning system around any issues, bottlenecks or constraints, again helping the project to manage risk.

This approach to assurance was a large-scale change for the ES team, many of whom were used to the traditional transactional process of draft-check-submit-edit around set formal review windows (as had been undertaken on previous phases of the project and the way most ES projects are managed). Initial concerns were raised with the concept of working with ‘live’ documents, overall ownership of the work and editorial control, and that work would be critiqued before internal checks and assurance had been undertaken, as well as IT related compatibility and back-up concerns. To engage the teams and encourage this cultural shift a number of resources were prepared including ‘how to’ videos, webinars, drop-in surgeries and a day-long conference at the start of the process to focus the teams on the new way of working and the preparation of the PWAPs.

During implementation it was found that there were different levels of engagement and integration across the topic teams which was sometimes due to the size or scale of their specific tasks, or the method or complexity of their topic’s assessment or simply due to individual’s working preferences and team relationships. In addition, due to the nature of the assessment work, the time it takes to resolve and work through issues as they emerge, and the time required for the teams to respond and feedback to the IAP could not always be followed in a firm and fixed way. The teams needed a level of flexibility to be able to manage and progress their work and, in response, the IAP had to be adjusted throughout to reflect this (with recognition that the overall programme would need to be maintained). It was also found that, in some circumstances, the windows for progressive assurance within the programme were narrow; again, flexibility in the IAP was a key mitigating factor, as well as maximising the use of live working on SharePoint allowing tasks to be undertaken in parallel or live on screen with a working group.

A further key learning is to give the topic teams space and trust, and to have confidence in a flexible approach to working, supporting them and avoiding too much management of the process. Topic teams were well versed in identifying and managing issues and challenges for their topics and had mechanisms to enable them to raise any risks and concerns.

A key reflection is that the approach to progressive assurance could be applied to the entire ES instead of solely focused on the Volume 5 and BID technical reports. This would enable better consistency across the documents and indeed could be considered for other scopes of work, disciplines and projects.


A key recommendation is to embed the progressive assurance approach across all HS2 Ltd ES deliverables and consider it for future large scale projects.

Progressive assurance and collaborative working should be seen as a key component for all future contracts producing large numbers of inter-related deliverables and should be outlined in their corresponding contracts, Quality Management and Delivery Plans.

Early project planning and onboarding would allow the supply chain to adequately resource this requirement for a project. Collaborative working should be considered a key requirement and integrated teams and the required tools and shared working platforms should be set up early to facilitate it.

This model could also be applied to other deliverables, such as engineering deliverables, to assist with a right first-time approach and efficiencies within the programme.


The progressive assurance and collaborative working approach was very successful and supported the delivery of the High Speed Rail (Crewe – Manchester) Environmental Statement on time to a high technical quality with ongoing confidence that risks were being well managed.

The progressive assurance approach led to an improved quality of technically compliant reports and mapping for the Phase 2b ES within a constrained programme. Whilst some of the individual assurance and certification processes may not be necessarily novel on their own, the combination of all of these tools and the collaborative way of working to implement the ‘three-lines of defence’ assurance process meant that HS2 Ltd had high levels of visibility and confidence in the robustness of the ES which reduced the risk associated with non-compliance with Standing Orders for a hybrid Bill submission.


Colleagues from MWJV, EOC, HS2 Central Environment, HS2 Environmental TSD.


[1] Three lines of defence assurance model as defined by the Good Governance Organisation Dec 2021  Accessed 23 October 2023

[2] HS2 Phase2b Crewe – Manchester Environmental Statement, HM Government from HS2 Non technical Summary, 24 January 2022. Accessed 23 October 2023

[3] HM Government Standing Orders  Accessed 23 October 2023

Supporting Materials

Peer review

  • Althea Jones