“Literally it was a leap of faith, jumping off the cliff at midnight in the dark.
“But knowing that somebody has the confidence in you and the belief in you – Wainwright is deeply persuasive as an individual, which I absolutely, really admire, I’m very grateful, always.”
Lancashire starred in Coronation Street from 1991 until 1996, appearing in more than 260 episodes.
She and Wainwright first met when they were “cutting their teeth” on the soap opera.
The pair later collaborated on the BBC comedy-drama Last Tango In Halifax, for which Lancashire won her first Bafta in 2014 for her supporting role.
They worked together again on Happy Valley, which ran from 2014 to 2023.
Asked what made playing Sgt Cawood so terrifying, Lancashire said: “The setting of it, being asked to play something which I had no knowledge of at all – absolutely no knowledge.
“And knowing that the level of research that was available to me was going to be quite limited in the time available.
“But in actual fact – as Wainwright always said – it wasn’t a procedural drama, it was not a police drama, it was a family.”