The agency saw off stiff competition from a shortlist that included three-time Consultancy of the Year Blue Rubicon to land the trophy.
The Campaign of the Year award went to Mandate Communications for Taking Exception, its work with the Rarer Cancers Forum that led to a policy change and an estimated £175m of extra funding for cancer patients.
Meanwhile Weber Shandwick saw off finalists Burson-Marsteller, Edelman and Text 100 and Highly Commended Four Communications to take International Consultancy of the Year. The PR team at RSA took Private Sector Department of the Year.
Public Sector Department of the Year went to Westminster City Council, and Macmillan Cancer Support scooped NGO Department of the Year.
Elsewhere within the Gold Awards, Sian Jarvis, director-general of communications at the Department of Health, was named PR Professional of the Year. Jarvis, who is profiled in this week's PRWeek, has spent ten years at the department and was voted most powerful healthcare professional in PRWeek's PowerBook 2008.