He succeeds Sir Adrian Montague, who has been chairman since 2008.
Mr Dilley joined Arup as a graduate engineer in 1976, became a director of Ove Arup & Partners in 1993 and was appointed head of Arup’s Europe and Middle East operations in 2004.
He is also a member of the prime minister’s business advisory group; chairman of governors of the Infrastructure & Urban Development Community at the World Economic Forum; a member of the Professional and Business Services Advisory Group, reporting to BIS; and a member of the Council of Imperial College. He steps down this month from being chairman of the CBI London Council.
Mr Dilley said of his latest appointment: “London is the main driver of the UK economy so we need to ensure that it maintains its position as the business capital of the world. With uncertainty in the Eurozone, it is imperative that we build strong links with the rest of the world, as well as reinforcing the links we have with our European partners.
“We need to make sure that London continues to attract the most talented people, maintains a vibrant business environment and delivers the world-class infrastructure needed to support growth. This is how we can help our businesses trade successfully with the world.
“These are all issues on which London First has taken a lead and I look forward to contributing to its work in the years ahead.”