In 2014, Lancashire re-united with "Last Tango in Halifax" writer Sally Wainwright on the crime drama "Happy Valley". Wainwright was keen to write another role for Lancashire after being "blown away" by her performances in "Last Tango in Halifax". Lancashire portrays single-grandparent Catherine Cawood, a police sergeant still dealing with the aftermath of her daughter's rape, and subsequent suicide, eight years earlier. Mark Lawson of "The Guardian" identified the performance as a career best for Lancashire, stating that she perfectly conveyed "the script's demandingly contradictory notes of tragedy, comedy, love, guilt, weakness and courage". For this role she earned the TV Choice Award for Best Actress in 2014, and the Royal Television Programme Award for Best Actress in 2015. In September 2014 the "Radio Times" listed her as one of the thirty most powerful women in British television and radio. In April 2015 she received her fourth BAFTA television nomination, her first in the Best Actress category. In June 2015 she was named Best Actress in a Drama Series at the Monte Carlo Television Festival.