The BBC in a 2014 ethics guide, "Forms of Euthanasia," available at bbc.co.uk, stated:

“Non-voluntary euthanasia occurs when the person is unconscious or otherwise unable (for example, a very young baby or a person of extremely low intelligence) to make a meaningful choice between living and dying, and an appropriate person takes the decision on their behalf.

Non-voluntary euthanasia also includes cases where the person is a child who is mentally and emotionally able to take the decision, but is not regarded in law as old enough to take such a decision, so someone else must take it on their behalf in the eyes of the law.

Involuntary euthanasia occurs when the person who dies chooses life and is killed anyway. This is usually called murder, but it is possible to imagine cases where the killing would count as being for the benefit of the person who dies.”

2014