Source: http://www.magnumphotos.com/Package/2K1HRGPK90EX

However, according to "The Grove Encyclopedia of American Art, Volume 1" by Joan M. Marter, the London office was opened in 1986

We also received note from Neil Burgess that "Peter was not a member of Magnum at this time, be was an associate and did support Chris Steele Perkins in getting the agreement from the membership to open an office in London. But CSP was the main 'pain in the arse' (according to Burt Glinn!) that lobbied the membership. The office opened in a serviced office at Panther House, just off Gray's Inn Road in May 1986. I was the first Director.

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