English: Shell-Mex House, London. Shell-Mex House, at 80 The Strand, London, was built for Shell-Mex and BP in 1935. During the war it was the HQ of the Petroleum board. When Shell-Mex and BP separated in 1975 the building became the HQ of Shell UK Ltd the UK company of the Royal Dutch Shell Group. The building was sold by Shell in the mid 1990s and Shell now only leases a small trading floor in the building.