Clarkson on Thursday appointed William (Bill) Thomas as Chairman.
Mr Thomas took up the role on Wednesday and would also chair the nomination committee, and serve as a member of the remuneration committee, the company said.
Mr Thomas had extensive international technology and management experience, gained through both his executive and non-executive careers.
He currently chairs Spirent Communications plc, listed on the London Stock Exchange, and Node4, an unquoted IT infrastructure and services provider. airs the Remuneration Committee and is a member of both the Risk Committee and the Nomination Committee. He is a member of the International Advisory Board of cyber security specialist FireEye, Inc.; and chairs the Board of Trustees of the Royal Navy & Royal Marines Charity.