Full-Auto Knife
Common Use Names:
Flick Knife, Switchblade, Automatic Knife
Cited:
The Restriction of Offensive Weapons Act (1959)
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
Any knife which has a blade which opens automatically by hand pressure applied to a button, spring or other device in or attached to the handle of the knife.
Common Misconceptions:
Rolox actions, Speedsafe actions (commonly referred to as semi-automatic knives) are not full-auto knives. Whilst they open in a similar fashion, they do not meet the criteria of the Restriction of Offensive Weapons Act (1959), as the device required to be operated to deploy the blade is attached to the blade itself, and therefore is not in nor attached to the handle of the knife.
EUROPEAN AUTOMATIC STILETTO
KNIFE, TYPICALLY OF GERMAN OR
ITALIAN ORIGIN
KNIFE, TYPICALLY OF ITALIAN,
SOVIET, OR EASTERN-BLOCK
ORIGIN
TRADITIONAL AUTOMATIC
AUTOMATIC OUT-THE-FRONT
(OTF) KNIFE, TYPICALLY OF ITALIAN
OR AMERICAN ORIGIN
MODERN FULL-AUTO AUTOMATIC
KNIFE, TYPICALLY OF GERMAN,
ITALIAN, AMERICAN, OR FAR
EASTERN ORIGIN
Gravity Knife
Common Use Names:
Paratrooper Knife
Cited:
The Restriction of Offensive Weapons Act (1959)
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
Any knife which has a blade which is released from the handle by the force of gravity or the application of centrifugal force.
Common Misconceptions:
This workable definition was adapted from the Monroe County, New York, USA statute, which goes further to state "When released, is locked in place by means of a button, spring, lever or other device". Although the stated act does not refer to this point it must be assumed that this is what is inferred.
LUFTWAFFE PARATROOPER
KNIFE, TYPICALLY OF GERMAN
ORIGIN
TRADITIONAL GERMAN GRAVITY
KNIFE, TYPICALLY OF GERMAN
ORIGIN
MODERN GRAVITY KNIFE,
TYPICALLY OF FAR-EASTERN OR
EAST-ASIAN ORIGIN
Stealth Knife
Common Use Names:
Airport Knife
Cited:
The Criminal Justice Act 1988 (Offensive Weapons) (Amendment) Order 2004
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
A knife or spike, which has a blade, or sharp point, made from a material that is not readily detectable by apparatus used for detecting metal and which is not designed for domestic use or for use in the processing, preparation or consumption of food, or as a toy.
Common Misconceptions:
None
COLD STEEL'S CAT TANTO IS
MADE FROM A SINGLE PIECE
OF HIGH-IMPACT RESISTANT
PLASTIC. IT LOOKS LIKE AN
ORDINARY KNIFE, BUT FEATURES
NO METAL COMPONENTS.
THIS COLD STEEL SPIKE IS ALSO
MANUFACTURED FROM A HIGH
IMPACT PLASTIC. HOWEVER,
SOME KNIFEMAKERS ALSO USE
OTHER MATERIALS, FOR
INSTANCE CERAMICS.
Disguised Knife
Common Use Names:
Hairbrush Dagger, Ink Pen Knife
Cited:
The Criminal Justice Act 1988 (Offensive Weapons) Order 2002
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
Any knife which has a concealed blade or concealed sharp point and is designed to appear to be an everyday object of a kind commonly carried on the person or in a handbag, briefcase, or other hand luggage (such as a comb, brush, writing instrument, cigarette lighter, key, lipstick or telephone.
Common Misconceptions:
Knives commonly referred to as 'credit card' knives are not disguised knives, as although they are similar in shape to a credit card, this is simply to facilitate storage and no attempt is made to design the knife to appear to be a credit card - with or without the benefit of closer inspection.
THE INK-PEN KNIFE PULLS APART
TO REVEAL A SHARP BLADE.
TYPICALLY OF FAR-EASTERN
ORIGIN, BUT SOLD AROUND THE
WORLD AS NOVELTY ITEMS.
FROM THE OUTSIDE THIS KNIFE
LOOKS LIKE A LIPSTICK. ROTATE
THE BRASS COLOURED BARREL
TO EXTEND THE BLADE.
TYPICALLY OF FAR-EASTERN
ORIGIN, BUT SOLD AROUND THE
WORLD AS NOVELTY ITEMS.
Belt-Buckle Knife
Common Use Names:
None
Cited:
Criminal Justice Act 1988 / Statutory Instrument 1988 No. 2019
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
A buckle which incorporates or conceals a knife.
Common Misconceptions:
None
THIS BELT BUCKLE KNIFE IS A
SINGLE PIECE BUCKLE. BELT
BUCKLE KNIVES ARE ALMOST
EXCLUSIVELY AMERICAN IN
SOURCE, ALTHOUGH MANY ARE
MANUFACTURED IN THE FAR-EAST.
THEY HAVE A PARTICULAR
AFFILIATION WITH MOTOR-CYCLING
GROUPS IN AMERICA.
THIS AMERICAN MADE BELT
BUCKLE INCLUDES A FOLDING
LOCK KNIFE. BELT BUCKLE KNIVES
ARE OFTEN DECORATED.
THIS BELT BUCKLE KNIFE
INCLUDES A FOLDING LOCK KNIFE.
Push Dagger
Common Use Names:
None
Cited:
Criminal Justice Act 1988 / Statutory Instrument 1988 No. 2019
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
A knife, the handle of which fits within a clenched fist, and the blade of which protrudes from between two fingers.
Common Misconceptions:
Utility knives designed specifically for the purpose of opening boxes or packaging materials, particularly certain types of martial-arts training knives. For instance, the Gil Hibben knife features a handle which fits within a clenched fist, but the blade protrudes from between the thumb and the forefinger; not two fingers.
THIS COLD STEEL SAFEKEEPER
IS THE TYPICAL PUSH DAGGER
SILHOUETTE. TYPICALLY OF
AMERICAN OR FAR-EASTERN IN
ORIGIN.
THIS IS AN AMERICAN MADE
MODERN PUSH DAGGER.
Balisong
Common Use Names:
Butterfly Knife
Cited:
Criminal Justice Act 1988 / Statutory Instrument 1988 No. 2019
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
A blade enclosed by its handle, which is designed to split down the middle, without the operation of a spring or other mechanical means, to reveal the blade.
Common Misconceptions:
Pentographic knives are not Butterfly Knives, but they do fully meet the description of a Butterfly Knife and one must assume that perhaps inadvertently or not, they are prohibited.
AMERICAN MADE BALISONG
BUTTERFLY KNIFE, TYPICALLY
OF FAR-EASTERN OR AMERICAN
ORIGIN.
THIS BALISONG KNIFE IS MADE
IN CHINA, BUT SOLD MAINLY
THROUGH USA RETAIL OUTLETS.
MOST OFTEN AVAILABLE FOR
SALE VIA THE INTERNET.
Sword Cane
Common Use Names:
Sword Stick
Cited:
Criminal Justice Act 1988 / Statutory Instrument 1988 No. 2019
Prohibits:
Manufacture, import, sale or hire, or offer of sale or hire, or lending or giving to any other person.
Legal Definition:
A hollow walking-stick or cane containing a blade which may be used as a sword.
Common Misconceptions:
None
SWORD CANES TYPICALLY FEATURE
ENGRAVED OR DECORATED
HANDLES. MANUFACTURED THE
WORLD OVER, INCLUDING MANY
BRITISH EXAMPLES MADE DURING
THE VICTORIAN ERA.
MODERN SWORD CANE FEATURES
A CROSS PATTERN BLADE AND
A PLAIN HANDLE.
I wasn't actually aware of the 'gravity knives' You've now filled my early quota for learning something new. 
