People walking along bankside by the south of Southwark Bridge may had never noticed a piece of history in their walks! It turns out some street bollards in the streets of London had previous use back in Napoleonic wars. Trafalgar naval battle is one the most notable British success during coalitions wars in the late 18th/early 19th Century. Napoleon Bonaparte emerged as a historic figure in conquering part of Europe as far as for reaching Russia. So Britain took part in these coalition wars.
The cannon here is from a defeated French naval vessel. When the British defeated the French it was common for them to disarm their vessels. French navy vessels ended up stripped from their guns by the victors. British army had a genius idea of stetting them up on their own ships but realized these guns didn’t fit in theirs. So they converted them into streets bollard to be spread out across London especially Central and East London. The Southbank one still remains today as many of them are no longer visible on the streets. For viewing it, Blackfriars station and London Bridge station are the nearest access.