Costain Group PLC is a United Kingdom-based technology-based engineering solutions provider. The Company offers consulting, project delivery, and operations and maintenance services. The Company operates through two segments: Natural Resources segment and Infrastructure segment. The Infrastructure segment operates in the highways, rail and nuclear markets. The Natural Resources segment includes the Company's activities in water, power, and oil and gas markets. The Company offers a range of services, including advisory and concept development, specialist design, program management, project delivery, technology integration, and asset optimization and support. The Company offers services across whole life cycle of its customers assets in energy, water and transportation business areas focused on the United Kingdom market. The subsidiaries of the Company include Costain Limited, Costain Integrated Services Limited, Costain Upstream Limited and Richard Costain Limited.