Martin Luther founded the movement that led to the modern British church as we know it, so I'm not sure what you think the UK government convicted him of?

In the case that you're confusing Martin Luther, and Martin Luther King, MLK was also not convicted by the British government of anything, and as this is a British government policy, I'm a little curious as to what relevance you feel this has on the discussion at hand...

I think that was Henry VIII that set up the COE

It's more complicated than that, but you could do worse than start with:

https://en.wikipedia.org/wiki/Protestant_Reformation

It would be up to the Pope to pardon Martin Luther as it was Pope Leo who excommunicated him for Heresy in January 1521…

…but lets not get into that—the last thing HN needs is another religious debate alongside those of iOS v Android and Node.js v everything.