Carillion has won a £90m support services contract with British Gas owner Centrica.
The contractor will deliver facilities management and project services for an initial period of five years, with an option to extend for a further two years.
The contract is scheduled to start in December.
Carillion has worked with Centrica for 10 years as a managing agent. This deal extends the scope of its existing contract to a total facilities management service.
Under the new agreement, Carillion will provide hard and soft facilities management services, including asset surveys and planning, planned and reactive maintenance, cleaning, security and catering for Centrica’s 115 locations in the UK and Republic of Ireland.
It will also include the delivery of certain construction projects for Centrica.
Carillion chief executive Richard Howson said: “We have worked closely with Centrica since 2005 and built a strong partnership.
“We are delighted to be extending this relationship, which is based on a one-team approach in which Carillion and Centrica work together to deliver award-winning standards of facilities management and customer service across all Centrica and British Gas sites.”