Yesterday marked a momentous day in the UK capital – the 10th anniversary of the ‘No Trousers Tube Ride’, an event which sees Londoners travel on the Underground sans kegs.

Brightly coloured knickers and boxers were on display as people took to the city’s transport network in honour of the event, hosted by the Stiff Upper Lip Society.

There isn’t really a reason for the tradition, other than to have a laugh. As its Facebook page puts it: “The point is to relax and enjoy the humour inherent in people not wearing trousers.”

The event kicked off at 2.30pm in front of the National Gallery in Trafalgar Square. People congregated, with their trousers still very much on, then headed to various Underground stations where they removed them. It was strictly a no thongs, “banana hammocks” and mankinis event – in the name of public decency (and, ya know, not getting arrested).

Rather brilliantly, the usually emotionless commute around the capital turned into a legs out free-for-all.