In the grotesque sequence, Daniel Smith (Thom Ashley) is dropped from the gallows and sliced open before his insides are ripped from his body as he issues ear-piercing screams.
The priest also has his hands and feet chopped off in the vile torture scenes, dubbed by one fan as one of the "most painful scenes on television".
And as if that wasn't enough, the executioner then goes onto proudly show off the priest's head as a trophy kill to the crowd after it is dipped it in tar.
Elsewhere in the show, Lady Dorothy (Sian Webber) is paraded through the cheering crowds in bare feet and a nightdress.
The humiliating scenes bare a striking similarity to that of Cersei's nude walk of shame in Game Of Thrones' iconic season five finale.
Lady Dorothy is then stripped to be executed and crushed beneath what appeared to be four kettle-bells.
Reflecting on the violent project, series star Harington hailed the historic drama as "his baby".
"I loved being involved as a producer in this from genesis, from coming up with the idea to finding a brilliant writer that wanted to do it with us, to finding a brilliant director who wanted to direct it with us, to casting it.
"You know, I was involved from the very start. I understand now what they mean when they say, 'It's my baby'."
Viewers, however, flooded social media with their disgust at its savage violence which left little to the imagination.
The BBC has defended the scenes, claiming they were historically accurate, and said that viewers were warned before the start of the show.
A spokesman said: "The scenes aired after 9.30pm with a clear warning given to viewers before the episode started.
"The methods depicted are grounded in historical fact and reflect what took place during the time of the gunpowder plot."
