Mercury House is an office building at 124, Theobalds Road, Holborn, London, which was the headquarters of Cable & Wireless from 1955. It was opened by John Reith and was named after the Roman god.
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The architect was Gordon Jeeves. The interiors were designed by H C Upton, Cable & Wireless's own architect. The three glass panels in the entrance were the work of John Hutton.
The building has been home to MediaCom since December 2006 .
51°31′12″N 0°07′12″W / 51.5199°N 0.1200°W