I suppose the more you train your police like your military, the more they're likely to use force and aggression to the extent that some american forces seem to employ on their citizenry.
Tazers were 'sold' the the british public as a non lethal option for firearms officers in a situation where a firearm would otherwise have been used. However that's not how they are used currently.
Mission-creep - at first it's only armed response units, now it's regular police. I think the problem with tools like these is that in some (though not all) cases, the threat response escalates more quickly, with improper use of such tools as means of coercion on individuals who clearly don't warrant such a response in the first place - think the blind guy who was tazered a while back.
Arming the police more heavily will lead to training them in a more aggressive fashion. That's just the way it goes.
I know there's a couple of you guys who stick up for the police due to your involvement. I don't really have any issue with that. But part of the responsibility of the uniform, along with the pension, the unsociable hours and the chance of seeing and being involved in some rather unpleasant things, is also to expect to be held to a higher standard than joe-public, to be placed under the scrutiny of the people and their criticism, no matter if you like it or agree with it or not.
There are certain cases that just show how bad the police can be when it comes to doing the right thing - the jean charles de menezes case stands a head an shoulders above many other cases of recent times - nothing about that, from the incident and it's control, to the press statements and subsequent distortion of what happened and why, to the blatant public smearing by officials of JCM, culminating in the charade of a public inquiry that was so utterly anaemic in its prosecution that the commanding officer (of the operational surveillance of a known terrorist suspect, who had been watched closely for more than six months), presided over such a catastrophic failure of communication followed by some of the worst official backtracking I have ever seen reported, not only kept her job, but was even promoted!
On the whole I think we have a better police force than the americans, but I certainly wouldn't call them great. Everyone can use example of how this country does this despite that, or how that country doesn't do this as a reason to explain how giving our police firearms won't change how they deal with the public. But if we give the police these tools, then they will use them, in some cases grossly inappropriately.
We can all sit here and argue about it; about how that guy deserved it 'cause he didn't do what he was told etc. But perhaps that guy might one day be you, going about your business to be suddenly faced with armed, aggressive police who are used to treating eveyone they deal with as a potentially lethal threat, and when you don't respond immediately to their commands, because you're and ordinary guy and not a hardened criminal and have no idea what is happening to you, and you do the wrong thing and end up dead, well.... we can all sit round here and moralise about how you 'should have done what you was told, serves you right'.
That is the reason why I find such cases so deplorable, when there is absolutely no reason for them to have happened in the first place, and when they do nobody accepts responsibility for killing someone they shouldn't have.
It's a trend that is not exclusively american and the only reason we don't have such comparable rates of police killings is because we do not arm our regular plod. The longer we can keep it that way the better.