I've desperately tried to avoid sticking my head above the parapet here, but there is an awful lot of ill-informed misconception about blades/pointed instruments, offensive weapons, arrest and search powers and the like.
Martyn is pretty much spot on with most of the legal stuff he has raised, but what most people are missing is the way the law is both enforced and developed in the UK.
Law is made both by parliament and by way of case stated, so that it develops as time progresses. The fundamental difference between UK enforcement and that in most of the rest of the world is that the Police are given significant discretion in how they enforce the law. Discretion is a fundamental concept in British policing.
Arrest powers were changed by s110 Serious Organised Crime and Police Act 2005 [
http://www.opsi.gov.uk/acts/acts2005/50015--k.htm#110. ] The discretion given to police is demonstrated by the phrases A constable
may arrest without a warrant and anyone whom he has
reasonable grounds for suspecting in other words, the police do not need to know that an offence has been committed, just to be able to justify their suspicion that one has, in order to arrest and that arrest is optional [
may arrest rather than
will arrest.]
Stop and search under s1 Police and Criminal Evidence Act 1984 the single most important crime prevention tool available to a patrolling officer IMHO similarly requires reasonable grounds. Stop and search when authorised by a senior police officer in apprehension of terrorism or public disorder, or searches authorised by warrants [e.g. pub raids] do not. The vast majority of stop-and search is carried out under s1 PACE84, and I can assure everyone that the average patrolling officer is far more likely to target a s1 PACE search at a known local criminal or tearaway than at the local vicar walking his poodle. It is for this reason that I suspect most members of this forum have never been, nor ever will be, searched in the street. Its strange that there is so much worry about it.
So, lets say you have a fixed-blade knife on you, in a rucksack with camping gear, on your way home from a weekend in the woods, and you get a tug for whatever reason. What happens next?
Policing is a peculiar trade and as much an art as a science. Individual officers personalities and communication skills do vary, but for the vast majority of officers, one of the first questions that is asked prior to searching is have you got anything on you I should know about? This is your opportunity to produce what you have and explain it, should you be carrying something which might for example be subject to s139 CJA88 and require a reasonable excuse. [A dim view is generally taken of things that are subsequently discovered.] Do you really think you are likely to get arrested under these circumstances?
Martyn has explained context and reasonable excuse pretty much to perfection, but if you are any doubt, just think if I was a jury member would I accept that this reason, on the balance of probabilities, justified the defendant having that specific item at that specific time and place for that specific use, there and then. This is why the its useful, I might need it reasons are not acceptable, and why I replaced my leatherman wave with a juice pro with non-locking blades.
Im old, and I remember life before s139 CJA88. The primary legislation to control knife violence was s1 Prevention of Crimes Act 1953 which created the offence of possession of an offensive weapon. This legislation was excellent and rightly is still in force. An off-weap is, as previously mentioned, anything made, adapted or intended to cause injury.
Examples of
made off-weaps include truncheons, knuckle-dusters and flick knives.
Adapted off-weaps are things like baseball bats with nails through them, motorbike chains with gaffer-tape handles, and the ubiquitous Jif [a squeezy lemon that has something other than lemon in it]. An
intended off-weap is an otherwise innocuous item that its owner intends to use as a weapon.
The average knife is not, and never has been, an offensive weapon, unless it is intended for use as such. Most knives are tools but have the potential to be used as weapons, just like axes, screwdrivers and claw hammers.
The requirement to prove intent when a local criminal was caught with a kitchen knife in his sock was problematic unless he made a verbal admission of some sort and few criminals give honest answers to police questions. [Obviously, a drunk crim waving the same knife about at 3am shouting do you want some of this would probably show intent to even the most dim-witted of people.]
This in essence is why s139 CJA88 was introduced. The effect of the legislation and subsequent case law is this if an individual was found with a knife or pointed instrument, other than a non-locking folding pocket knife with a blade of less than 3 inches, the onus was now on that individual to explain why they had it, not on the police to prove that the individual was intending to use it as a weapon.
From my point of view, it was a superb piece of legislation. If you disagree, then perhaps you would like to consider a known street robber who is seen by police following a little old lady away from a post office on pension day. [Known street robber, pension day, following little old lady from post office = reasonable grounds to search in my book.] Suppose the known street robber is searched and found with an ice pick [this is the sort of pointed instrument to which the legislation refers, not a pencil for heavens sake please let common sense prevail.]
Now, you would like that street robber to be arrested, wouldnt you?