Underground commuters are gearing up for their annual trouser-less Tube ride this Sunday as Londoners commemorate the US version of No Pants Subway Ride.

This Sunday marks the seventh annual

This Sunday marks the seventh annual trouser-less Tube ride across the London Underground stationsImage by See Li / CC BY 2.0

This weekend will mark the seventh annual flashmob day and organisers expect over 1000 people to show more undercarriage than usual on their Sunday train journeys.

No Pants Underground Ride has become a celebration to silliness across many of the world's major cities

No Pants Underground Ride has become a celebration to silliness across many of the world’s major cities Image by digboston / CC BY 2.0

The group stress that there is nothing really for the authorities to get their knickers in a twist over. They are just groups of friends having a bit of fun as they board at a number of city Tube stops with less leg cover, despite the cold weather, than usual.

Part of the act is that those who participate act as if they’re strangers and the dress sense is totally normal.

Pranksters Improv Everywhere began the novel travel dress in New York 14 years ago. Since then, the Evening Standard reports that the group leader, Charlie Todd, and his “undercover agents” have undertaken scores of “missions,” sometimes accompanied by special music themes.

The Group’s website says it all started out as a small-time prank but has grown exponentially to become an internationally recognised celebration in silliness.

The two major obstacles to the dress-down day has been extremely cold weather conditions and transport authorities. The largest scandal associated with the day surrounded an incident 10 years ago when eight almost nude New Yorkers were reportedly handcuffed in their briefs and taken into custody.

However no charges were pressed as it is not against the law to appear in public with just underwear on in the Big Apple.

The advice for London wannabee members of the trouser-less group is to be nice and friendly and to eschew thongs or skimpy underwear that might cause offence.