Today's RMT strike means some commuters face a denuded service, but London Underground was totally pants over the weekend. Hundreds of pranksters stripped down to their underwear for the annual No Trousers On The Tube Day.

Known elsewhere as the No Pants Subway Ride, the event began in 2002 in New York with only seven participants and has grown into a global phenomenon, with events in more than 60 cities. The day is coordinated by Improv Everywhere, a global flash mob, who call it "an international celebration of silliness".

The idea is for trouserless participants to board a train and maintain a nonchalant air, listening to music, reading newspapers, while keeping a straight face as if all were perfectly normal. The participants wear typical winter clothing on their top half such as hats, scarves and gloves and do not acknowledge each other's similar state of undress. IBTimes UK presents photos commuters taking part in the annual No Pants On The Subway Ride around the world.