In setting these net zero targets, we committed to reducing our emissions as far as possible, and offsetting the residual emissions at the target years. During 2023, our near-term targets, which support our net zero targets, were validated by the SBTi (Science Based Targets initiative). This provides independent assurance that our projected emissions reduction trajectory is aligned to the ambition of limiting global warming to  1.5°C. The trajectory towards net zero is unlikely to be linear, and in some years, we may see our emissions increase as the volume and mix of projects changes.

Net Zero Route Map

In support of our science-based and net zero carbon targets, we have developed and published our net zero route map. The route map identifies 16 activities where action is required in order to achieve our emission reduction targets. These include: the use of diesel, company vehicles, site compounds, permanent offices, business travel, design, construction materials, emissions measurement, internal carbon charging and offsetting. For each of the activities, the route map outlines the timeline of the actions we have already taken or are underway, the actions we still need to take, and our ultimate ambition.

For the activities that contribute towards our scope 1 and 2 net zero by 2030 target, the actions are more specific because we have a greater degree of control over these activities, we have better data, and the target year is closer. For the activities that contribute towards our Scope 3 net zero by 2045 target, the actions through to the target year are less well-defined, and will continue to evolve as we develop more accurate emissions measurement techniques and engage with our clients and supply chain partners on low carbon materials and construction methods.

The route map is intended to be a guide for our teams across the business to understand the actions they need to be taking and when. It also is a means of communicating to our clients, supply chain and other stakeholders the journey we collectively are on and the role we need them to play.

Achieving net zero through our Carbon Reduction Plan 

Policies and management

Our Environmental Policy sets out our commitment to integrating the assessment, management and control of environmental issues into the management of our business. This is complemented by our Energy Policy, which recognises the impact of energy use on climate change and commits us to effectively and efficiently managing our energy use. Our Biodiversity Policy obligates us to protect and, where appropriate enhance biodiversity during our construction activities. Our Responsible Sourcing Policy requires us to consider our preferred suppliers’ environmental impacts, among other issues.

We identify, manage and mitigate our environmental impacts from project to business level through our ISO 14001 certified management system, supported by a network of Health, Safety and Sustainability (HS&S) advisors.

Our policies and processes are contained within our BMS (Business Management System), a mandatory platform, which defines our approach to all key operations and sets out the standards we must adhere to. Use of the BMS ensures consistency, governance and control and effective risk management by mitigating issues at source.

We make our people aware of our environmental standards and policies that are integrated into our BMS through extensive training, our intranet and by promoting our Code of Conduct, ‘Doing the right thing’, to all our employees.

Ensuring compliance

Compliance with our environmental policies is assessed through HS&S advisors who are aligned to each business unit to provide support and advice. They visit sites regularly to ensure compliance with policies and procedures and produce a Safety, Security and Environmental Report, which is communicated to appropriate levels in the business through a database. Any non-compliance identified requires a corrective action plan, including the date by which it will be completed.

We also monitor performance using key performance indicators (for example covering waste and timber), which are regularly reviewed and variations investigated. Any incidents or visits (for example by the Environment Agency) are logged in databases and reported to divisional Boards each month.

In our Annual Report (published in October), we make disclosures in line with the recommendations of the Task force for Climate-related Financial Disclosures (TCFD), including outlining the key risks and opportunities that climate change poses to our business.

1. 42% reduction by 2030, based on 2021 baseline.
2. Restated to reflect disposal of Rock & Alluvium.
3. 42% reduction in total Scope 3 by 2030, based on 2021 baseline.

Scope 1 and 2 carbon emissions

Scope 1 and 2 carbon emissions Our Scope 1 emissions predominantly relate to fuel use in company cars and vans, and on-site plant and equipment. Our Scope 2 emissions relate to consumption of electricity across our sites and permanent offices, and EV charging of company cars.

In 2024, our Scope 1 emissions relating to company cars and vans continued to trend down, reducing by a further 12% compared to 2023, as we complete the transition to EV/Plug-in Hybrid Electric Vehicles (PHEVs). This was partially offset by a 30% increase in Scope 2 emissions relating to EV charging of company cars. However net emissions across both scopes reduced by 8%. As at 30 June 2025, full battery electric and plug-in hybrids represented 98% of our company car fleet.

Emissions relating to the use of diesel on our sites increased to 9,185 tonnes CO2e (2023: 4,612 tonnes CO2e) in the year. This was driven by several factors, the most significant being:

High rates of growth in our Highways and Environment businesses, which have the highest intensity of diesel use.
Increased use of diesel-powered pumps to dewater sites, due to exceptional levels of rainfall.
Increased use of diesel generators as a result of delays in getting connections to the mains electricity grid.
As outlined in our Net Zero Route Map, which we published in September 2024, we are committed to achieving diesel-free construction by 2035. We have refreshed our guidance to staff on opportunities to reduce our use of diesel through deployment of energy-efficient plant and equipment, and transitioning to lower carbon alternative fuels. Our Green Site set-up Working Group continues to engage with the industry and our projects to find new opportunities. We will continue to monitor the impact through improved diesel reporting.

Because electricity represents an increasing proportion of our Scope 1 and 2 emissions, and we purchase 90% of our electricity on renewable tariffs (2023: 86%), we use market-based Scope 2 emissions within our headline Scope 1 and 2 emissions KPI. This also aligns with our science-based target, which reflects market-based Scope 2 emissions. The market basis uses emissions factors that reflect our actual electricity supply contracts and therefore allows us to demonstrate the impact of purchasing our electricity on renewable tariffs. The location basis uses the average generation mix for the UK and as such, is susceptible to changes that are outside of our control.

Our total Scope 1 and 2 emissions increased 41.2% year-on-year on a market basis, and by 35.0% on a location basis. These increases were driven by the significant increase in emissions relating to diesel used on site, offset slightly by the net reduction in emissions relating to company cars and vans. Growth of the business has a significant impact on both Scope 1 and 2 emissions. We therefore monitor emissions intensity, measured in tonnes (t) of carbon dioxide (CO2) equivalent (tCO2e) per £100,000 of revenue in the corresponding calendar year, to provide a clearer picture of the impact of our emission reduction initiatives.

Our Scope 1 and 2 (market-based) emissions intensity increased by 15% from 0.69 in 2023 to 0.79% in 2024. This reflects the fact that the highest rates of growth are in our Environment and Highways businesses, which have the highest intensity of diesel use. Despite these increases, we have reduced our reported Scope 1 and 2 emissions by 51% since 2012, and by 59% on a like-for-like basis, adjusting for acquisitions, disposals and improvements to methodology. We remain committed to achieving our target of achieving net zero by 2030.

Verified Scope 3 emissions

We include certain categories of Scope 3 emissions within the boundary of the external verification where we have sufficiently reliable source data, such as business travel expense claims, and information regarding employee commuting to calculate emissions using a distance-based method. Our verified Scope 3 emissions increased by 22.4% from 7,128 tonnes CO2e in 2023 to 8,874 tonnes CO2e in 2024.

The biggest contributor to this increase was ‘Fuel and Energy Related Activities’, which increased by 34.7% and is an estimate of the  transportation, transmission and distribution losses associated with the energy use reported in Scope 1 and 2. Emissions from Business Travel and Employee Commuting increased by 24% and 15% respectively. These increases reflect the growth in employee numbers, as well as an increase in air travel.

Waste intensity

Our waste intensity decreased from 17.7 tonnes per £100,000 of revenue in calendar year 2023 to 12.4 tonnes per £100,000 of revenue in calendar year 2024. Waste continues to be an area of focus, with increased use of Modern Methods of Construction, especially off-site manufacture, which can reduce the volumes of waste produced. Our focus on Right first time also reduces waste, through increased accuracy of materials required. We also manage our waste streams to maximise recycling and minimise waste to landfill, with 96.0% of our waste diverted from landfill (2024: 95.3%).

The effective management of water resources is of growing importance both in terms of managing our operational risk and protecting the natural environment. More regular intense rainfall events increase the risk of run-off from our sites, while periods of high temperatures and drought conditions can put restrictions on activities that require water usage, such as dust suppression and use of welfare facilities. Our project environment plans already include a water management section which addresses management of consents for water abstraction and discharge, and water course pollution control. However, we also recognise the importance of responsible use of water resources, including measures to reduce water consumption. Therefore, we have started recording water consumption data as part of our environmental reporting and will use this to establish baseline performance and to inform the development of water reduction targets.

Carbon Disclosure Project (CDP)

We continue to participate in the CDP, a global disclosure system for organisations to manage their environmental impacts. In 2025, we retained our score of B ‘Management level’, recognising the progress we are making in embedding climate action into our governance, strategy and operations.