Shriver joined Tulchan in 2009, having been director of financial comms and strategic adviser to the chief executive at Carrefour.
In addition to his client work, Shriver is charged with managing and growing the firm as well as ensuring best quality service across the agency’s client portfolio.
Tulchan founder Andrew Grant commented: "I, and all of my colleagues, are very pleased that David is taking on the role of managing partner. He has been with Tulchan for five years and in that time has earned the respect and affection of all of us in the firm. He will focus on accelerating the development of talent within Tulchan and our offer to clients."
Meanwhile, both Buchanan and Andersen-Tuffnell will join Tulchan in January.
Buchanan will join as a partner from Maitland where he has been a senior partner for two years, having previously spent 18 years at Brunswick.
Andersen-Tuffnell will join in a new role concentrated on public policy and stakeholder engagement. He has held the role of director of government affairs at the BBA for the past four years.Grant said: "Tom and Ben bring proven and valuable experience and will increase the depth and range of our advisory offer to clients.
He added: "We are having a strong year across the firm, particularly advising on IPOs. So far this year we have advised on five, with a combined market capitalisation of around £10bn."
Tulchan advised Royal Mail Group on its financial comms during its recent privatisation and is currently acting for both tourist attraction group Merlin and tech firm Servelec on their London IPOs.