This is a thought that has struck me. I've never seen it on here before, so heres my idea. What if James VI of Scotland was killed whilst making good his escape during the Huntingtower plot?
At this point, Lady Anne Stanley was down as the heir apparent to the throne of England, with the death of James you would see the Stuart claim to England destroyed and a hardcore Protestant on the throne of Scotland.
How do you think this would play?