You need to be at least 18, and, if it is a curved sword, cannot be over 50cm in length. Exceptions are as follows:

•Members of historical re-enactment groups which hold a Public Liability Certificate.

•Members of a Martial Arts club which hold a Public Liability Certificate.

•Use for authorized Theatrical / film use.

•All Swords over 100 years old.

•Samurai Swords made before 1954.

•Samurai Swords made in Japan at any time using the traditional forging technique.

Then new exemptions rolled in:

•Where only swords made using ‘the traditional technique’ in Japan were exempt, this has now been widened to cover swords made anywhere in the world "according to traditional methods of making swords by hand"

•Also, it is now permitted to import / make / buy a sword for the "purpose only of making the weapon available for the purposes of use in religious ceremonies".