Senior police officers have been warned to look out for a new knife which can inject a ball of compressed gas into its victim that instantly freezes internal organs.
The 'wasp knife', which can deliver a ball of compressed gas capable of killing its victim at the press of a button, may be heading for Britain, the Metropolitan Police fear.
A needle in the tip of the blade shoots out the frozen ball of gas which instantly balloons to the
size of a basketball, freezing organs.
The Metropolitan Police have told colleagues in the West Midlands to be on the lookout for the blade, which is designed to kill sharks and bears.
Police fear that the 'wasp knife' - designed to kill bears and sharks - may soon hit the streets of Britain
Police are concerned that the £200 weapon could fall into the wrong hands.
The American-made weapon is sold to hunters and divers and injects the frozen gas when the small handle-mounted trigger is pressed.
The manufacturer describes it 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."
Labour MP for Perry Barr in Birmingham, Khalid Mahmood, said: "Weapons like this are absolutely disgraceful and there is no reason at all why people should be walking around the streets with them.
"There should be high-profile operations and high-profile arrests against anybody caught with them. The way to tackle the wider issue of knife crime is with effective community policing, which the West Midlands force does very well.
"The Met could pick up on the lessons from West Midlands Police in its excellent community work in places like Handsworth, Aston and Lozells."
The Wasp injection website states: "The effects of the compressed gas not only cause
overinflation during ascent when used underwater, but also freezes all tissues and organs surrounding the point of injection on land or at sea."