The BBC reported he was on a trade mission. The Sun speculated he was in Libya. Somewhere in Africa, offered the Sunday Times. Others suggested the Foreign Affairs Council in Luxembourg. Red Box got it the most wrong:

Whitehall source says Boris Johnson is currently in the foreign office…

— Matt Chorley (@MattChorley) June 25, 2018

Boris has surfaced in Afghanistan, the game given away by the Afghan Ministry of Foreign Affairs…