Following the Cabinet Office briefing chaired by our beloved Prime Minister, this, apparently, is now the official mode of greeting, meant to take the place of a hand shake. The idea has been taken from the method recently introduced by the Chinese called the 'foot-touching curtsy'. Costumes are, unfortunately, mandatory. We've Special Advisor Dominic Cummings to thank for that particular directive. God knows why.
No idea if it'll catch on, but the new design for antibacterial masks would seem to blend in seamlessly.