Neal Street producing three-part festive special with full series to follow

The BBC has unveiled further details of its previously announced Call the Midwife prequel, set during World War Two.

Neal Street will produce 3 x 60-minute Christmas special Call the Midwife: Sisters in Arms, which is now filming at Call the Midwife’s studio home in Longcross, Surrey. This will be followed by a full-length series of the same name, details of which are yet to be revealed.

The prequel will be helmed by the title’s current creative team, including showrunner Heidi Thomas, and will feature younger versions of some well-known characters from the BBC1 hit, which is set to conclude with the forthcoming 16^th series.

Kicking off in September 1939, the special will follow a group of nuns dedicating their lives to helping poor mothers and babies with no gas and air, penicillin or welfare state to aid them. When war breaks out, life gets even harder as the blackout and the Blitz take hold.

The nuns will be played by Julie Hesmondhalgh (Mr Bates vs the Post Office), Amy Booth-Steel (Down Cemetery Road), Helen Schlesinger (Ted Lasso) and Helena Wilson (The Hills of California). Their trusted Dr Kit Malhotra will be played by Bally Gill (Slow Horses).

The spin-off was ordered by BBC drama director Lindsay Salt, created, written and exec produced by Heidi Thomas, exec produced by Pippa Harris for Neal Street, Jo McClellan for the BBC and Ann Tricklebank.

Tricklebank will direct episodes one and two with John Maidens directing episode three.

Thomas said: “Having loved and lived with the Sisters of Nonnatus House for so many years, I found myself longing to turn the clock back and tell the story of their finest hour – the Blitz.

“Above all else, Call the Midwife: Sisters in Arms is about what happens when women go to war. It is about love and birth, separation and courage, lipstick and nylons (or the lack thereof).

“But it is also a medical drama, set in a devastating landscape where even the nurses cannot know if they will live till morning.”

Harris said: “It echoes the original through its blend of engrossing medical stories, wit, and pathos, while the backdrop of WW2 adds a completely fresh layer of tension and jeopardy to the drama. Heidi’s extraordinary skill with character and story means viewers are in for a real treat this Christmas.”