No Trousers Tube ride: Londoners take part in stunt to 'make people laugh'

Half-naked London commuters braved the bitter cold in their underwear and boxers - all in the name of humour.

People ride on a London Underground train as they take part in No Trousers on the Tube day, in London.. Picture date: Sunday January 7, 2018. Source: AAP

More than 400 willing participants rode the iconic London Underground without trousers on Sunday, as part of the No Trousers on the Tube Ride initiative. 

Some braved the cold in their fun underwear, others chose boxer shorts, bringing a smile to bewildered fellow commuters.

It's part of a global initiative with the objective to "make people laugh, not piss them off".

A man waits on the platform at Bond Street tube station as he takes part in No Trousers on the Tube day, in London. Source: AAP

Passengers wear no trousers as they ride the London Underground in London, Britain, 07 January 2018. Source: AAP

The initiative started as No Pants Subway Ride in New York in 2002 and has since taken place across the US and Europe.

The UK-based Stiff Upper Lip Society has urged other nations to take part.

The rules include: "Willing to take trousers off on the Tube and able to keep a straight face about it."

People wait on the platform at Liverpool Street tube station as they take part in No Trousers on the Tube day, in London. Source: AAP

Men use cash machines at Liverpool Street station as they take part in No Trousers on the Tube day, in London, Sunday, January 7, 2018. Source: AAP

Passengers wear no trousers as they ride the Jerusalem's light train in Jerusalem, Israel, 07 January 2018. Source: AAP

People wait on the platform at Bond Street tube station as they take part in No Trousers on the Tube day, in London. Source: AAP

Despite freezing temperatures on the east coast of the United States, New York subway commuters also took part.

Many bundled up with coats to bear the brunt of the cold, with participants gathering in a snow-covered Union Square afterwards.