Police officer tweets picture of 15-inch knife left in a London stairwell

Sergeant David Hunt made the discovery when he was called to reports of youths smoking cannabis in south east London

PC Osborne holds up the terrifying blade (Sergeant David Hunt)

They say pictures speak louder than words – and that was certainly the case when a police officer tweeted an image of a huge knife left on an estate in south London.

The knife, measuring approximately 15 inches in length, was abandoned in a stairwell of Perronet House, near Elephant and Castle in the borough of Southwark.

Metropolitan Police Sergeant David Hunt had been called to investigate reports of youths smoking cannabis, but the perpetrators fled the scene.

Sgt Hunt posted a picture of his colleague, Police Constable Osborne, holding the terrifying weapon and tweeted: “Just seized this knife maybe saved another life? Unfortunately didn't catch the youth carrying it.

“The worrying thing is why did they have it in the first place?”

Twitter users expressed their shock at the discovery. @skibum999 said: “That's not a knife, it's a bloody cutlass! Why the hell would you carry something like that about?!”

Meanwhile, @thehugheslady tweeted: “That is a nasty looking weapon. Scary that anyone should carry this.”

Users were also vocal in their praise of the Met’s efforts to combat knife crime in the capital. @SellinSheffield tweeted: “Awesome work, well done and thanks for making the streets safer.”

And @anyross37 said: “Just saw the photo! Excellent job by the team getting that off the streets. My blood ran cold just looking at it!”

Fortunately, Sgt Hunt doesn’t make such finds every day.

“This sort of thing is very unusual for my ward,” he tweeted.