Call the Midwife creator: ‘People tell me birth stories in the supermarket’

Thomas has also managed to write endless fresh storylines, reflecting the health and social issues of the era.

“People ask me every year, ‘Where do you get your stories from?’

“And the simple answer is, I go into the British Newspaper Archive, or I go into the medical archive, or people come up to me in the street.”

This is what made her decide to write about sexually transmitted diseases in the upcoming series in January.

“In the health report for Poplar [in London’s East End], there was this brilliant description of how gonorrhea was getting out of control, and the Greater London Council instigated tracing teams of middle-aged women,” she says.

“I just thought, ‘this is Miss Higgins’ – I love Miss Higgins.”

Miss Higgins, played by Georgie Glen, is the prim surgery receptionist with a poignant family backstory, which revealed her hidden strengths.

“I think all good drama takes you by surprise,” Thomas says.

“The stories I choose to tell are the ones that grab me by the throat or the heart.

“I never know which organ is coming under pressure.

“But there’s this kind of ‘Wow’ moment, when I see things that actually happened, and then that feeds into the fictional process of developing the drama.”