RSK Group
RSK Group is a privately held United Kingdom-based environmental, engineering and technical services group built through organic expansion and extensive acquisitions.
Last updated August 31, 2026
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Overview
RSK Group is a diversified environmental, engineering and technical services group headquartered in Helsby, Cheshire, with origins in Aberdeen. Founded in 1989 by Alan Ryder, the business has developed from an environmental consultancy into a large privately owned platform containing more than 200 operating companies. Its activities span environmental consultancy, agriculture, ecology, water, geotechnical and civil engineering, infrastructure, construction support, planning, surveying, rail, energy, risk management, research, facilities services and related technical disciplines. The group’s expansion has been driven by a combination of organic development and a sustained acquisition programme. Early transactions included Structural Soils in 2007 and Dynamic Sampling and JB Site Investigations in 2016. The acquisition of ADAS in late 2016 was a major turning point: ADAS was then the United Kingdom’s largest independent agricultural and environmental consultancy and brought approximately 300 employees into the group. RSK subsequently acquired businesses across engineering, acoustics, ecology, water, site investigation, architecture, planning, construction, rail and infrastructure. More than 70 businesses were acquired during the six years to 2022, and the group continued adding companies in 2023–2025. RSK’s portfolio includes specialist consultancies as well as operational contractors and technical service providers. The model allows the group to offer services across the project lifecycle, from environmental assessment, planning and design through construction, infrastructure maintenance, monitoring and operational support. Prominent businesses associated with the group have included ADAS, WRc, MWH Treatment, Binnie, RSK Biocensus, PD&MS, 1stInRail and other specialist companies. Individual subsidiaries generally retain their sector expertise and, in many cases, their established names while operating within the wider RSK platform. The company has pursued ambitious scale targets. In 2021 it stated an objective of reaching £1 billion in turnover and 10,000 employees by 2025, while later plans targeted turnover above £5 billion and approximately 400 businesses by 2030. Growth has been supported by private-credit and private-equity financing, including a £1 billion sustainability-linked debt facility arranged in 2021 and a further investment package announced in 2024. These financing arrangements have also produced substantial interest and finance costs, and the group reported pre-tax losses in several consecutive financial years despite strong revenue growth. Reported revenue increased from £274.8 million in the year to April 2020 to £350.5 million in the year to April 2021, £796 million in the year to April 2022, £1.22 billion in 2023, £1.9 billion in the year to March 2024 and £2.2 billion in the year to April 2025. The figures reflect both acquisitions and expansion of the existing businesses. The group reported an operating profit in 2024 and 2025, but finance charges continued to contribute to significant pre-tax losses. By 2025, RSK described itself as employing approximately 14,500 people across its broad international network. Its positioning is that of a privately controlled, multidisciplinary platform serving environmental, infrastructure, engineering and sustainability-related markets.
History
RSK Group was established in Aberdeen in 1989 by Alan Ryder. It began as an environmental and technical consultancy and expanded progressively into related engineering and advisory disciplines. Structural Soils joined the group in 2007, followed by Dynamic Sampling and JB Site Investigations in 2016. The late-2016 acquisition of ADAS substantially increased RSK’s scale and broadened its agricultural, environmental and land-management capabilities. From 2017 onward, RSK adopted an increasingly active acquisition strategy. It added civil and structural engineering, geotechnical, acoustics, ecology, non-destructive testing, architecture, planning and environmental businesses. A £140 million unitranche funding package arranged in 2018 supported a further programme of acquisitions. Transactions in 2018 and 2019 included Cole Jarman, Ian Farmer Associates, Twig Group, CAN UK Holdings, J&A Pelling, Dr Tillmans & Partner, Headland Group, Biocensus, Raw Technology, Geocore, Ecologia, ATP Architects + Solutions and Silcock Leedham Group. The acquisition programme continued in 2020 with Salix River & Wetland Services, Nicholas O’Dwyer, Morrison (Falklands), WRc and Black & Veatch’s United Kingdom and Asia water and environment businesses. The latter transaction led to the revival of the Binnie name for part of the acquired operation. In 2021, RSK acquired or added businesses including CAS, CR Civil Engineering, Enviresearch, EDP Health, Safety and Environment Consultants, Orbital, SkyVision, The Scan Station, Smith & Kennedy Architects, Stephenson Halliday, Waldrams, Althoff & Lang, Quality Solutions International, Minerex Environmental, TechnikGS, CS2 and Leap Environmental. A major 2021 transaction was the acquisition of MWH Treatment, a large United Kingdom water business. Other additions that year included Carbon Zero Consulting, Envireau Water, Enviroflow, Streetwise, Centara, Hi-Line Contractors, Optisol Services, Non Entry Systems and ATV Contract Services. In August 2021, the group arranged up to £1 billion of sustainability-linked debt facilities. The pricing mechanism was connected to progress on carbon intensity, health and safety, and ethical performance, with RSK stating that part of any interest saving would be directed to sustainability or charitable initiatives. The acquisition pace remained high in 2022. RSK acquired Singleton Clamp & Partners, Fishtek, Inis Environmental Consultants, Richard Allitt Associates, Ceetech, ADEV Environment, MG Scaffolding, MSS Group, Milestone Communications, Spencer Group, Copper Consultancy and Travis Baker. By October 2022, the group comprised more than 175 companies and employed around 10,000 people. In 2023 it added WysePower, BMG Research, 1stInRail, PD&MS, Larsen Water Management, Global Infrastructure Group and RJT Excavations, strengthening its temporary-site-services, research, rail, energy and civil-engineering activities. During 2023–2024, RSK stated that it intended to expand internationally and reach more than £5 billion in revenue by 2030. It announced plans for additional equity funding and, in 2024, secured preferred equity investment led by Searchlight Capital Partners and Ares Management funds together with a £300 million debt facility. The group continued acquiring businesses, including EB7, Apollo Strategic Communications, 3BM Group, Kendall Kingscott, Edge Impact, Pegasys and Elsym Installations. In February 2025 it acquired the N-Able Group, including ECD Architects and Keegans, expanding its building consultancy, retrofit and fire-safety capabilities. Later announcements covered AGEA in Latin America and Octavius Infrastructure in the rail and highways sector. Financially, RSK’s growth has been accompanied by significant borrowing costs. Revenue rose from £350.5 million in the year to April 2021 to £796 million in 2022 and £1.22 billion in 2023. Pre-tax losses were reported in those periods, with interest expense a major factor. Revenue reached £1.9 billion in the year to March 2024 and £2.2 billion in the year to April 2025. Operating profit was positive in both periods, but investment and finance charges produced pre-tax losses. The group therefore represents a notable example of an acquisition-led private environmental and engineering platform whose scale and geographic reach have expanded rapidly while its financing structure has remained an important business consideration.
- 2025
RSK reaches approximately £2.2 billion revenue
[1]Revenue for the year to April 2025 reached £2.2 billion, with approximately 14,500 employees reported.
- 2024
New equity and debt package announced
[1]Searchlight Capital Partners and Ares Management funds led a preferred-equity investment alongside additional debt capacity.
- 2023
International and infrastructure expansion accelerates
[1]Acquisitions included BMG Research, 1stInRail, PD&MS, Larsen Water Management and Global Infrastructure Group.
- 2022
Group surpasses 175 companies
[1]Following numerous acquisitions, RSK reported more than 175 companies and approximately 10,000 employees.
- 2021
Sustainability-linked financing and MWH Treatment acquisition
[1]RSK arranged up to £1 billion of sustainability-linked debt facilities and acquired MWH Treatment.
- 2020
WRc and Black & Veatch water businesses acquired
[1]The transactions strengthened RSK’s water research, consultancy and engineering portfolio.
- 2018
Acquisition financing supports further growth
[1]RSK secured a £140 million unitranche senior debt facility to fund acquisitions.
- 2016
ADAS acquisition marks a major expansion
[1]RSK acquired ADAS, materially increasing its agricultural and environmental consultancy scale.
- 2007
Structural Soils joins the group
[1]The acquisition expanded RSK’s site-investigation and geotechnical capabilities.
- 1989
RSK Group founded
[1]Alan Ryder established the group in Aberdeen as an environmental and technical services business.
Products and positioning
A privately held, acquisition-led multidisciplinary environmental, engineering and technical-services group serving public- and private-sector infrastructure, energy, water, construction, agriculture and sustainability markets.
Consulting services
Environmental and sustainability consultancy
Services include environmental assessment, permitting, sustainability advice, climate-related work, ecology, biodiversity, land management and regulatory support for infrastructure, energy, agriculture and construction projects.
Engineering and technical services
Water and wastewater services
Through businesses including WRc, Binnie and MWH Treatment, the group provides water research, consultancy, design, project delivery, treatment and infrastructure services for public and private-sector clients.
Engineering services
Geotechnical and civil engineering
RSK companies undertake site investigation, geotechnical analysis, civil and structural engineering, ground services, highways, drainage and infrastructure works supporting development and major construction programmes.
Agricultural consultancy · 2016
Agriculture and land management
The ADAS business provides agricultural, environmental, land-management, research and advisory services, making agriculture and rural resource management a substantial part of RSK’s portfolio.
Infrastructure services
Rail, highways and infrastructure services
The group’s infrastructure companies provide rail renewal and repair, highways, temporary site services, telecoms-related engineering and civil works, extending RSK beyond consultancy into operational delivery.
Brand decisions
2024
Preferred-equity investment to support strategic takeoversM&ABackground
RSK continued to pursue acquisitions across environmental consulting, infrastructure, property and technical services.
Action taken
A consortium led by Searchlight Capital Partners and Ares Management funds provided preferred equity, supplemented by a £300 million debt facility.
Aftermath
The financing was intended to support expansion from approximately £1.2 billion of turnover toward more than £5 billion by 2030 and a portfolio of about 400 businesses.
Additional debt facility. £300 million (June 2024)
2023
Capital-raising plan for acquisitions and international expansionStrategyBackground
Rapid acquisition activity had made RSK one of the largest privately owned environmental and engineering groups, and management sought additional capital to continue scaling.
Action taken
RSK announced plans to raise approximately £500 million through a sale of shares, alongside roughly £500 million of existing backing, to fund further acquisitions and international growth.
Aftermath
The stated long-term ambition was to reach approximately 40,000 employees and £5 billion of revenue by 2030.
Planned new equity capital. £500 million (August 2023)
2021
Adoption of sustainability-linked financingStrategyBackground
RSK required substantial funding to support an acquisition-led growth plan while presenting sustainability as a core part of its environmental-services identity.
Action taken
The group arranged up to £1 billion of debt facilities whose pricing was linked to carbon intensity, health and safety, and ethics-related targets.
Aftermath
RSK stated that it expected interest savings if targets were met and would direct at least half of the margin benefit toward sustainability initiatives or charitable causes.
Debt facilities. £1 billion available facilities (August 2021)
Recent events
- 2025
RSK revenue reaches £2.2 billion[1]
Other
For the period to April 2025, reported revenue rose to £2.2 billion and the group said it employed about 14,500 people, although finance charges continued to weigh on pre-tax results.
- 2025
RSK acquires AGEA in Latin American expansion[1]
M&A
RSK announced the acquisition of AGEA, an environmental consultancy with a significant Latin American presence.
- 2025
RSK acquires Octavius Infrastructure[1]
M&A
The group announced the acquisition of the rail and highways business Octavius Infrastructure from Sullivan Street Partners.
- 2025
RSK reports rapid revenue growth but continuing pre-tax loss[1]
Other
For the year to April 2025, RSK reported revenue of approximately £2.2 billion. Operating profit declined to about £4.2 million, while investment and finance charges contributed to a pre-tax loss of approximately £124.5 million.
- 2025
RSK announces acquisition of AGEA[1]
M&A
RSK announced the acquisition of AGEA, an environmental consulting firm with a significant presence in Latin America, extending the group’s international environmental-services footprint.
- 2025
RSK announces acquisition of Octavius Infrastructure[1]
M&A
RSK announced the acquisition of the rail and highways business Octavius Infrastructure from Sullivan Street Partners.
- 2025
RSK acquires N-Able Group[1]
M&A
RSK acquired the 110-person N-Able Group, including ECD Architects and Keegans, strengthening its building consultancy, retrofit and building-safety capabilities.
- 2024
RSK agrees further private-equity investment and debt capacity[1]
M&A
A consortium led by Searchlight Capital Partners and Ares Management funds provided preferred equity investment, alongside an additional debt facility, to support strategic takeovers.
- 2024
RSK secures new private-capital and debt funding[1]
M&A
A consortium led by Searchlight Capital Partners and funds managed by Ares Management provided approximately £500 million of preferred equity, alongside an additional £300 million debt facility, to support further acquisitions.
- 2024
RSK reports £1.9 billion revenue for year to March 2024[1]
Other
Revenue increased by approximately 52% to £1.9 billion. Although operating profit was positive, finance costs contributed to a reported pre-tax loss of about £132 million.
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