The law in this area falls under Section 1 of the Prevention of Crime Act 1953 which defines the offence of having an offensive weapon as follows:
Any person who without lawful authority or reasonable excuse, the proof whereof shall lie on him, has with him in any public place any offensive weapon shall be guilty of an offence.
In this context, 'public place' is anywhere which members of the public have access to. This would include parks, cinemas, car parks, sports halls, supermarkets, etc.
An 'offensive weapon' in law is defined as anything that is made, adapted or intended to cause injury to a person.
An offensive weapon that is offensive per se is said to be 'made for causing injury to the person'. Examples of such weapons would be swords, throwing stars, knuckledusters. These items are made for one purpose and one purpose only and that is to cause injury to a person.
The next class of offensive weapon is any weapon 'those adapted for causing injury to the person', such as a bottle with the end smashed off or a baseball bat with nails poking out of it.
The last category of offensive weapon is 'those not so made or adapted, but carried with the intention of causing injury to the person', for example a Stanley knife, biro pen, brick, umbrella; the list is endless. As long as a person had that article with him and intended to use it to cause injury that would suffice.
Defences in law to the offence of possessing offensive weapons are, firstly, lawful authority. This would be available, for example, to a police officer who would have lawful authority to carry weapons. The other defence is reasonable excuse. This has a wide variety of applications, for example, it is a reasonable excuse for a chef to have a knife in public if he is taking it to work. It is a reasonable excuse for a carpenter to have a hammer if he possessed it in the course of his employment. Other reasonable excuses include self-defence. For example, if you are expecting an imminent attack then it may be a reasonable excuse for you to pick up or to have a weapon for immediate use.
The reasonable use heading can also be available to martial artists in relation to weapons that they might be carrying. Therefore, if a martial arts weapon is purely made for the use of teaching, then it is not an offensive weapon. If, however, it is made to cause harm and its secondary use is an implement to teach, then it would be an offensive weapon. Most martial arts weapons fall into this category. You have a reasonable excuse to carry an offensive weapon to a place of further education to which any martial art is a source of physical arts education. Therefore, a defence is applicable under reasonable excuse. However, it is not a defence to take any weapon to a park, supermarket, the pub, or any other public place. You must take it home immediately after training. If it is not reasonable at the time to do so then this could be a defence, but the onus is on the person to prove this.
Although there are defences, do not expect this to protect you from arrest. You could be arrested if the police constable has any suspicion to believe that an offence has been committed and your legal defence would have to be proved. If the Crown Prosecution Service believe that just by virtue of you possessing an offensive weapon there is enough evidence to charge you and take you to court, then it is up to you to show on the balance of probabilities that you had a reasonable excuse for possessing the offensive weapon in question. Invariably, a reasonable excuse in this context would be that you were going to or returning from training. If you forget to take your weapon out of your car after you return home from training and you continue to have it in your motor vehicle when you are driving it for purposes other than going to or from training, then the defence of reasonable excuse may not be available to you.
Therefore, best practice would be only to have a weapon on you if you are going to or coming back from training. In addition, it is best to have that weapon in the boot of a car if you are driving, and to certainly have it well covered and next to your training suit.
The defence of reasonable excuse would be available to anyone training with wooden weapons such as a bokken (sword), jo (short staff), bo (long staff) or a tanto (dagger). Although not strictly relevant for the purpose of martial arts, the following are also examples of weapons that can be possessed with a reasonable excuse:
antique weapons - generally over 100 years old lock knives - i.e. with blades which fold into the handle that can be opened manually and locked into place crossbows - except for use by unsupervised persons under 17 years old swords, bayonets, machetes - except for concealed swords or swordsticks axes, hatchets, tomahawks throwing knives replica medieval weaponry such as spears, lances, pikes, maces, caltrops and halberds blowpipes and blowguns for use by vets and registered animal handlers
However, it is unlikely that reasonable excuse would succeed as a defence regarding the following, as their manufacture, import, sale, hire, offer of sale or hire, lending, or giving to any other person is prohibited under statute. It would therefore be best practice not to have these weapons in a public place:
knuckledusters, handclaws and push daggers footclaws - i.e. spikes designed to be strapped to the foot flick or gravity knives - i.e. with blades that are spring-loaded or can be opened using gravity or a flick of the wrist weapons with a concealed or disguised blade or sharp point - e.g. swordsticks, stealth knives, butterfly knives and belt buckle blades martial arts weapons such as death stars, hollow kubotans and kusaris batons and telescopic truncheons blowpipes or blowguns, except for use by vets or registered animal handlers curved blade swords with a blade over 50 centimetres
There are exceptions to the import and possession restrictions on swords with a curved blade of 50 centimetres or over provided that the weapon:
if it was made before 1954 or made by traditional sword-making methods if it is only available for the purposes of use in religious ceremonies or for martial arts if it is for use in a 'permitted activity' for which public liability insurance is held
Permitted activities include historical re-enactments or a sporting activity, e.g. martial arts demonstration. The martial art of Iaido would fall into this category. But with this martial art, above all others, it is important to keep the weapon well wrapped up in transit and only take it into a public place if going to or returning from training.
All students have to carry his/her weapon on the bag or a special weapon holder.
Not allowed to keep it in the car next to you, without the holder.