Ahead of the finale everyone's talking about, Mairead spoke to Hannah O'Connell all about her obsession with the BBC's most successful drama - Line of Duty.
Hannah said there are two ways to watch the show - you can just let it wash over you, or you can do what she does and read into every little detail and do some AC-12 level detective work yourself.
Hannah and her friends Rebecca and Brendan are hosts of the Shrine of Duty podcast where they give weekly recaps of the episode along with predictions and fan theories, and their guests include the man behind the waistcoats, Martin Compston himself.
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You can hear the chat in full by pressing the play button on screen.