The Mayor of London was speaking at the launch of the new 4G network from EE. He thanked the telecommunications operators for their work throughout the London 2012 Olympic Games.
However, he struggled to name all of the companies, including one of the official Olympic sponsors, reports the Daily Telegraph.
He said: "I want to say thank you now to all of them, to Vodafone, to er...I'm allowed to mention Vodafone, aren't I, in this context?
"I want to thank Orange, who've been everywhere, T-Mobile, who've been everywhere... I want to thank... who are the other guys?"
He then quickly remembered to mention BT, an official partner of the London 2012 Games, much to the amusement of those in attendance.
In pictures - Boris Johnson's best moments as London Mayor:
Boris Johnson takes part in a scientific experiment at the Royal Institution in central London to officially launch the Story of London festival.
1 of 15
Copyright: PA Images
