Users of the Piccadilly line, prepare to recoil in horror.
The Metro has published a picture of a man sitting on a train, which would be fine if not for the fact his pants are down! Yes, he's sitting bare-bottomed on the seat, and we can all agree you just don't do this on the Tube.
Following this man's obvious violation, we thought it was time for a quick reminder of the rules of the London Underground
Despite them all being unspoken, they are law, and you risk incurring the fiery wrath of all Londoners if you break them.
Check out the gallery above!