I think the word is homicide, not murder. Many of the deaths are criminals shooting one another, police shooting criminals, and even a few citizens defending themselves from criminals. There are more suicides than murders, and those are counted as homicides, too.
In order: murder is the unlawful pre-meditated decision to kill. (That can be 20 seconds or two years)..Accidental death or causing death (for example) when driving a vehicle can be charged as manslaughter in certain circumstances*; and frequently in a court case both charges (murder and manslaughter-I think in the US it's called 2nd degree murder) will be on the sheet, so the prosecution have the option of falling back on manslaughter if the defendant is acquitted of murder. Suicide here is called suicide and not (thankfully) treated as a crime in itself..Of course it puts a different complexion on things if the suicide is preceded with the killing of others.
In the UK the police are governed by protocols for the deployment of armed officers. We have dedicated armed response units, and something called SCO 19; which is the specialist firearms command. They deal with things like sieges, terrorist attacks, hostage taking, and support for non armed officers in the cases of drug den raids etc. It's worth mentioning that the police have successively voted over the years to not be universally armed. The armed units are trained to an exceptionally high standard, and have adopted many of the practices, equipment and body armour used by special forces. Not every officer who applies is selected, and they go through psychology testing as well as of course ability to shoot accurately (at the right target!) under extreme duress. Even at the end of all that, every single incident involving firearms that results in the death or injury (and it's seldom injury, they never shoot to wound) results in the Independent police complaints commission investigating it. They have the power to bring prosecutions if they feel the police officer in question shot someone (or even fired the weapon) unlawfully.
It's my understanding that in the UK, you can't defend yourself with a knife or a club, either. Is that true?
Not so; you can defend yourself using reasonable force up to and including the resulting death of the person you feel might put you or your family in peril. In fact a guy recently did just that over near Manchester and killed a burglar (one of two), and although the police went through the process of arresting him, he was released without charge.
The 'reasonable force' has been open to contention but was recently re clarified by judges and the Director of public prosecutions; It essentially means if you feel at the time you need to break his legs, nose or run and sit on him that results in his ribs bursting through his lungs and killing him, then so be it. If you're a farmer and use a shotgun, again, if you feel that you or your family is in peril, then as long as you can give justified reason to shoot him, you'll be viewed sympathetically. However if the guy is running away and you shoot him in the back, it won't be a good day for you.
If so, what will you do when the EU comes for your wallet?
Why would they do that? We don't use the Euro as our currency in the UK is the pound sterling. Cyprus parliament has just voted against the proposal to steal 10% of their deposits' in the banks..However it now means their prime minister has to go to Putin and plead for a deferral on the billions that Russia has loaned them..time will tell how that plays out. Either way, it's not looking good for the Euro using member states; with the exception perhaps (but not certain) of Germany and France.
* There is the charge of causing death by dangerous driving. Which can include but not exclusive to alcohol/drugs, including prescription medication being involved. There is also death by misadventure; so for example you may be mountain climbing with your buddy, but because the rope snags it causes a successive but catastrophic series of events and he falls to his death. It's no-ones fault, but it's still a death that wasn't natural.