in this case it's warranted ... but considering how much crime punishment is incorrectly delegated and how many people are wrongly accused, i would not trust a government with the power to do that.
especially not govm't workers who're meting out this martial justice who work for PRISONS. they already abuse their power ... i shudder to think of how much they'd abuse THAT level of power. or what kind of person would want a career in mutilating people.
plus the UK banned executions, didn't they? so they'd have to mutilate these people, then have the taxpayers pay for them to get treatment to stay alive ...