(UPDATE: Originally posted on BB Gadgets)

Police in London are on the lookout for £200 frozen-gas knives designed to kill bears and sharks, according to the never-inflammatory Daily Mail.

The manufacturer describes [the Wasp Knife] as perfect for downed pilots, soldiers and security guards and boasts that it will "drop many of the world's largest land predators".

It can snap-freeze all tissue and organs in the area surrounding the blast.

A source close to West Midlands Police said: "The Met is obviously concerned about this and that is why they have circulated the information.

"This knife will almost certainly kill and the Met must have intelligence that they are in circulation.

"I think it is only a matter of time before one of these is used because the internet makes it much easier to find and buy weapons like this."