Volutary Manslaughter requires the defendant to have intended to kill or to have had an intention to cause GBH. The usual procedure is to charge murder / attempted murder. The jury may then have the opportunity to convict of manslaughter if a statutory defence is satisfied, one of which can be Diminished Responsibility. Diminished Responsibility must be an abnormality of mind at the time of killing. I suppose that extreme provocation could cause an abnormality of mind, but I doubt that a jury would consider some pillock on a bike twatting your TT to be sufficient provocation.
Quite right, not sufficient. Kudos to you for knowing the requirements for voluntary manslaughter, I didn't know that.
The loss of control defence is basically for the tragic situation known as 'battered wife syndrome', where the battered partner snaps unexpectedly, and for parents whose children are in imminent danger, that sort of thing. 'Considered desire for revenge' not allowed. Must be circumstances of extremely grave character, and causes defendant to have a justifiable sense of being seriously wronged. Has to be a response which an ordinary person in that situation would have.
The abnormality of mind defence isn't to be confused with provocation/loss of control, which is a separate defence. I didn't learn my criminal black letter properly, it's very interesting though.