The meeting, between Langdon and the network's chief executive and chairman John Dooner, resulted in Langdon's seven-year stint at McCann-Erickson being brought to an end.
UK chief executive Chris Hunton will continue to run the agency's UK office, while McCann-Erickson deputy regional director and vice-president David Warden will take temporary charge of its EMEA operation until a succession plan is formalised.
Landgon's resignation comes six months after that of Tamara Ingram, who resigned as chairman and chief executive of McCann-Erickson UK in January, and just weeks after the agency parted company with its chief strategic planning officer Paul Twivy and Universal McCann regional director Brian Jacobs.
The shake-up in Europe follows Dooner's ousting as Interpublic chairman and chief executive and the accounting scandal that centred on McCann-Erickson.
Dooner was moved sideways back to running McCann-Erickson, but James Heekin, chairman and CEO of McCann-Erickson Worldwide, was not so lucky and lost his job.
It was Heekin's McCann-Erickson that was at the centre of accounting discrepancies that forced Interpublic to restate $181.3m (£115) in earnings. The scandal also claimed the scalp of Sal LaGreca, chief financial officer of McCann-Erickson.
Dooner was replaced by David Bell, who was the head of True North until it was bought by Interpublic in 2001. Bell took the role of vice-chairman of Interpublic and was responsible for the division known as The Partnership, until the scandals of last year saw a reshuffle of senior management.
It led to wider claims of pressure from senior executives at Interpublic to improve the financial performance of the agency.
Ingram's departure followed a disappointing performance as the agency failed to get on various pitch lists, including that for the Orange account and having to compete for Coca-Cola work with Mother.
Ingram joined McCann in October 2001 after 16 years at Saatchi & Saatchi, the last six years of which she was UK chief executive.
In the wake of her departure, Langdon took charge of McCann-Erickson before appointing Hunton as the agency's chief executive.
The appointment was part of an agency restructure that resulted in a spate of high-level departures, including managing partner Chris Macleod, executive planning director Julian Saunders, and business development director Stephen Colegrave. All three were brought in during Ingram's year-long tenure.
Hunton reported to Langdon, who took on the UK chairman role in addition to his existing roles. With Ingram gone, Langdon committed himself to taking on a more active interest in the day-to-day running of the UK agency than he did while Ingram was the chief executive.
At the time, Langdon said: "It was time for the agency to pare back. January tends to be the month when difficult decisions like this are made."
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