Another day of butts in the streets :

Pranksters staged a cheeky invasion of London's underground network to take part in No Trousers On The Tube Day

Mailonline  reported that Pranksters staged a cheeky invasion of London’s underground network to take part in No Trousers On The Tube Day.

What began as a madcap idea by a handful of people on New York City’s mass transit system in 2002 has grown into an international celebration of silliness

Rail passengers averted their gaze as men and women stripped down to their underwear on the tube 
Now there are around 9,000-10,000 people who take part each year in the global good-willed stunt.

We have been running it for eight years here.

“We travel the Tube on the first Sunday of the year and just make a scene. We make people smile. We make people laugh and we get some lovely reactions.”Organiser Ivan Markovic said

Londoners wearing coats, hats and scarves on their upper half and nothing but underwear, socks and shoes down below braved the winter weather to take part in the wacky craze

On this year's Facebook page organizers The Stiff Upper Lip society said: 'The point is to relax and enjoy the humor inherent in people not wearing trousers'