No Pants Subway Ride Day started with just seven men in New York 12 years ago has ballooned to become an event recognised in over 60 cities in more than 25 countries.
The self-proclaimed “prank collective” group Improv Everywhere first came up with the idea when they performed the inaugural No Pants Subway Ride in 2002.
During the middle of winter, participants wearing winter coats, hats, scarves and gloves – but crucially no trousers, tights or skirts – board the same subway train at different stations, acting as if nothing is out of the ordinary.
That simple prank, which now has its own back story starring an unsuspecting woman caught up in the middle of it all (see video below), has “grown into an international celebration of silliness”, the group said.
According to Improv Everywhere, Sunday’s 13th Annual No Pants Subway Ride included over 4,000 participants in New York alone.
The Facebook organiser of the London event (given the name No Trousers Tube Ride) said over 150 Londoners took part last year, and came up with a detailed plan to ensure the prank mirrored the original as closely as possible.
Rammi Glomp said: “As there aren't as many people taking part like the original New York event, the plan is to divide ourselves up along the route so that passengers in a couple of carriages on one train get a surprise of seeing trouserless people getting on at every stop.”
Improv Everywhere describe themselves as having completed “100 missions involving tens of thousands of undercover agents”, and there was a hint of a secret briefing to Mr Glomp’s instructions, which read: “Do not talk to others once you enter the station. Nobody knows each other.
“If questioned, you do not know any of the other trouserless riders. Tell folks that you 'forgot to wear trousers' and yes, you are 'a little cold.' Insist that it is a coincidence that others also forgot their trousers. Be nice and friendly and normal.”
As well as taking place in London and New York, the prank brought in participants from Mexico City, Buenos Aires, Istanbul, Munich, Berlin (see gallery above), Prague, Paris, Shanghai and Hong Kong.