'Call The Midwife' is expected to have at least three more series.

Heidi Thomas

Heidi Thomas

BBC bosses have already confirmed that an 11th series of the show will air next year, and it is thought the medical drama will continue into series 12 and 13, which will cover the years 1968 and 1969.

A source told The Sun newspaper's Bizarre TV column: "'Call The Midwife' may have been around for nearly a decade but it is still going strong and providing the Beeb with a Sunday night ratings winner.

"There was no way the corporation were going to axe a show which has such a strong following and so much more scope for storylines.

"Continuing the show into series 12 and 13 sees the programme enter one of the most exciting periods in recent history.

"And there are currently no signs that the Beeb or the show’s team want to end the show there."

Meanwhile, Stephen McGann thinks his wife Heidi Thomas - the show's creator - deserves more credit.

The 58-year-old actor - who plays Doctor Patrick Turner in 'Call The Midwife' - believes the period drama is one of the best TV series of recent years.

He told Radio Times magazine: "Heidi has got grandma sitting down with grandchildren to watch a drama about abortion and the illegality of homosexuality.

"And how? Because she doesn’t bludgeon them over the head. It’s a fist in a velvet glove."

Stephen also thinks the show - which first launched in 2012 - offers "escapism" to viewers.

He said: "If people want to slump on the sofa before the trials of their working week resume, then it does offer a degree of escapism.

"But because we also tell important stories about major things in life, it’s also possible to dig deep and find meaning."