The truth behind one of the oldest fictions in history can finally be told.
The Catholics were in danger of wresting influence from Robert Cecil who had managed to remove Queen Elizabeth's favourites and put himself at the forefront of political power. King James, easily influenced, especially by a pretty face, male or female, needed to be restrained, especially with his profligate spending.
Cecil had three goals, therefore: remove the Catholic nobility, limit Puritan influence and endear himself to the king by becoming even more favoured than the pretty boys at court, the most influential of them had saved James's life.
The Puritans were dealt with by the king at 'The Hampton Court Conference' and that left the Catholics and the pretty boys. If he could only hatch a plot to discredit the Catholics and save the king at the same time, he would remove any potential opposition and earn the king's undying gratitude, put him above all others in the king's estimation. So he did!