Gritten (pictured) said her departure was for personal reasons as her family has recently relocated to Cambridgeshire. She will be joining a small agency in Cambridge.

She said: "I have thoroughly enjoyed my time leading the UK arm of Future Thinking and am immensely proud of our teams and best in class client delivery. I wish the Future Thinking Group all the very best for its evolving future and am sure it will continue to go from strength to strength."

Gritten’s departure comes at a time of change for the agency with John Dembitz, its non-exec chair, and David Griffith, group company secretary, also leaving. The position of its group CEO, James Stevenson, remains unclear.

Simon Mason has been appointed as executive chairman, replacing Dembitz. He said: “We would like to thank Adele for her fantastic service to the business over the past four years. The market conditions in the UK at the moment are difficult but the business has very supportive stakeholders who recognise the value in the future of the Future Thinking Gemseek Group. I am looking forward to working with them to help deliver a transformation of the business."

Jonathan Brod, managing partner, Next Wave Partners, said: "Next Wave has been an investor in the Future Thinking Gemseek Group since 2008. We are very supportive of Future Thinking Gemseek and continue to see great potential for the group as it navigates difficult market conditions in the UK and manages strong international growth."

In August the company closed a new round of financing with investment from  Next Wave Partners, Beechbrook Capital and Access Capital Partners.

Future Thinking acquired Bulgarian-based Gemseek Consulting and its subsidiary cQuest in 2016.