Doner has shuttered its London office, leaving the US-founded agency without a base in the UK.
The Drum has learned that the UK arm of the business was shuttered last month, affecting around 20 permanent members of staff.
It's understood the decision was taken in part due to one of the agency's largest clients, Huawei, making changes to its marketing set up. This has included centralising some creative work for its P20 Pro and P30 Pro smartphones with global agencies in China.
Since 2016, Doner has been one of Huawei's key EMEA agencies along with FCB Inferno.
The latter, which has worked with the brand since the end of 2017, continues in its remit and has been unaffected by Huawei's advertising shake up.
At the time of writing, Huawei had not responded to The Drum's requests for comment.
A Doner spokesperson said: “After careful deliberation, we made the decision to close Doner’s operations in London, and we continue to wind down our presence and operations there as part of an orderly transition plan.
"These decisions are never easy, and we are doing everything we can to help transition our employees and clients. Doner continues to build momentum in the US, following several new business wins in recent months."
The agency said that building out its US presence would be a priority moving forward, adding: "We are focusing our future growth efforts and investments on our US-based offices and are energized by the modern creative solutions and breakthrough work we are delivering for clients."
The Detroit-founded shop first landed in London in the late 1980s to serve BP. In 2015 it tapped former Addison Lee marketing boss Nick Constantinou as managing director. Constantinou was also previously a stalwart within AKQA.
As recently as 2017 the MDC Partners-owned agency had earmarked London as being crucial to it growth.
The agency still has offices in Detroit, LA, Southfield and Norwalk in the States.