I am sorry to resurrect an old thread, but, it seems that MANY UK people are confusing Lawful with Legal. Do some research and find that carrying a kubotan keyring is not unlawful.
I have a kubotan on my keyring and never had to use it. Once I went to the USA by car and was told by the US custom agent to go to the search zone. The custom officers looked at my keys and asked me what the object (the kubotan) was for and if it was hollow. One of them made fun of me and said its used to kill vampires. They were more concerned about me sneaking a joint than anything else.
Well played my good sir, well played. And no my kubotan doesnt really have a pointed end per say, more like a very rounded one like the black one at the bottom of the page http://www.tbotech.com/kubotans.htm