Comparing guns to kitchen knives is indeed silly. One is a designed as a weapon to maim and kill, the other is designed to carry out kitchen tasks. No doubt it can be used to maim and kill, but that is not it's purpose.
Also, those that say the bad guys will still carry guns aren't completely correct. To an extent that will be true, but I bet you fewer bad guys will carry guns. Fewer still would carry guns if the police were unarmed also.
The UK is a dump, but one of the few things going for it is unarmed police. Sure there are bad guys with guns, but your average criminal does not carry a gun as there is no need for one. There is no arms race between the good guys and the bad guys.
