image, London's oldest agency has left the dilapidated premises at 40 Berkeley Square, scheduled for demolition, for refurbished offices in Knightsbridge.
The move incorporates a restructure designed to encourage integration between the agency's departments.
The agency has ditched the traditional creative department and now creatives will sit with account handlers and planners in "client hubs".
Senior managers will no longer have closed offices as the entire agency goes open-plan in design.
Simon Bolton, the chief executive at JWT London, said: "We will be able to physically structure ourselves in a fashion that is more in tune with today's business world.
In acknowledging our clients' increasing need for integrated marketing communications we will no longer work in departmental silos so that our people with multi-talented skills will be able to group and interact with one another with greater ease."
Brushing aside criticisms that creatives may not prefer to be deprived of a traditional creative department, Bolton said: "Creatives have been told the story and told where we are coming from. We've been very thoughtful to ensure senior creatives have plenty of space.
"People have been preparing for this for six months. Some have been excited; some are circumspect and perhaps cynical. People are working in a different way already."