Call The Midwife’s creator says that she will not feature sex on the hit TV drama.

The series, set in the East End in the 1950s and starring Jessica Raine, Jenny Agutter and Miranda Hart, is returning to BBC1 for a third series later this month.

Heidi Thomas, the creator and writer of the period drama, told the Radio Times that she wanted to show ‘chaste romances’, which contrasted with the relationships that ‘girls have today’.

“We’ve never had sex in Midwife and we never shall,” she told the magazine.

“We have the consequences of it, certainly, but I always try to look at things within the historic context.

“In the East End of the 1950s – or so a lot of people have told us – children playing out in the street would see the midwives arrive and they thought the babies came in the box on the back of the bike.

“We’re not a soap, we’re a medical drama, but we do tell a story about women in the 1950s and it’s quite nice to show these rather chaste romances, which are so different from the ones girls have today.”

Heidi told the magazine: “It’s important, as well, always to acknowledge that the Call the Midwife stories were based, originally, on memoir, and that they’re always looked at through the filter of hindsight.”

Heidi has revealed previously that she had been told that applications for midwifery courses had increased since the show, featuring the nurses and nuns of Nonnatus House, went on-air. But she admitted that she had not been told the same thing about nuns. “I haven’t heard that there has been an increase in people wanting to be nuns. Maybe I just haven’t been informed,” she said.

Series three, which begins next Sunday, features Chummy (Miranda Hart), who is now a married mother, making a return to Nonnatus House and a love story between a woman who has Down’s syndrome and a character who has cerebral palsy.