Been through this mate...the above is wholly incorrect. If you have read the pace codes of practice.it shows that the point of searching and the idea of giving us a power of search is to avoid an unnecessary arrest. therefore with no evidence of an offence you should not be arresting for it. nor would it conform to human rughts act plan. it is not necessary or accountable.
I don't think you've quite got what I was saying. If you have enough suspicion for a search, you have enough suspicion for an arrest. If you had no grounds for suspecting that they had with them the relevant articles for a S1 search then obviously you wouldn't be searching them and you wouldn't be arresting them.
As for unnecessary arrest- an arrest is entirely necessary in a circumstances where someone has run away from a S1 search into a house as there is no other way you can lawfully apprehend/detain the person for a search.
I think it's ludicrous to suggest (if you are) that you should simply let the person go if you were in hot persuit and suspected them to have a weapon/knife/article for use in theft/burglary/fraud.
Whether this action comforms to the Human Rights Act or PLAN is a matter of debate, unless you have case law regarding the HRA which shows that the actions I have suggested would be unlawful.