Happy Valley's director, Fergus O'Brien, has heightened anticipation for the final episode even further, by confirming that the BBC drama will have a 'rollercoaster' ending.
As soon as it made its debut in 2014, Happy Valley became a huge ratingts winner for BBC One, as viewers were immediately invested in the exploits of Sarah Lancashire's on-screen alias, Sergeant Catherine Cawood and the many trials and tribulations she had to contend with on the beat and in her private life.
While there have been sub plots, such as one of her colleagues killing a woman he was having an affair with in series two, the back bone to Happy Valley's action has been the bitter war between Catherine and her sworn enemy, Tommy Lee Royce, the villain who raped and impregnated her young daughter Becky, with her later taking her own life after giving birth to son Ryan.
