Youth worker Shaun Thompson, and Silkie Carlo, director of campaign group Big Brother Watch, brought the challenge over concerns that facial recognition could be used arbitrarily or in a discriminatory way.
In a major victory for the continued roll-out of the technology, the High Court rejected claims that the Met Police had broken human rights and privacy law by scanning faces in public.
The force will continue to use the technology, with commissioner Sir Mark Rowley calling the ruling an “important victory for public safety”.