Solid ratings were expected when BBC1 launched its 1950s medical drama Call the Midwife last January in the primetime Sunday night slot vacated by Downton Abbey.
One year on, not only has it become the most successful new drama series in more than a decade, pulling in more than 10 million viewers – it has also inspired thousands of young people to consider midwifery as a career.
With a second series launching this month, applications to universities from budding midwives are up by 17 per cent according to Ucas – equivalent to an extra 3,000 students.
Terri Coates, a professional midwife adviser to the series, described yesterday how she was accosted by a midwife tutor from Glamorgan, who told her the usual 200 to 300 applicants for her course had risen to 1,000, adding: "You have made my life really difficult."
Mothers at the maternity hospital closest to the disused Catholic seminary in Mill Hill, north London, where the series is filmed, are eager to volunteer their newborns to appear in the series. Ms Coates trains the actors using prosthetic babies, cleverly made and correctly weighted.
When the real ones are substituted, they are allowed only 20 minutes on set, with the heat turned up to protect them from cold. If it is not warm enough filming cannot begin. Each shot must be meticulously planned.
"Once the babies are beyond four or five days they look too old. So the mothers must be approached in late pregnancy. But some are born late and some too early. The assistant directors have a [long] list of names but end up with only one or two. I think it's their biggest headache," Ms Coates said.
Jennifer Worth, the former midwife on whose memoir the series is based, died shortly before filming began. Her three-volume best-seller has spawned a clutch of imitators including The Midwife's Here! by Linda Fairley, Tales of a Midwife by Maria Anderson, and Catching Babies: A Midwife's Tale by Sheena Byrom.
Sales of replica vintage bikes, of the kind ridden by Miranda Hart, are also up, and fashion editors describe a new interest in collars and curls.
The secret of its success is still a matter of conjecture. The babies are important – even the crew have been seen to melt when they appear and a hush falls over the set. Critics who have complained it is sanitised and sentimental admit the casting works, mixing fresh faces with veterans such Jenny Agutter and Pam Ferris. Miranda Hart is a big draw.
Some say it would never have succeeded had its way not been smoothed by Downton Abbey. A gritty response to a glam blockbuster has become a blockbuster in its own right.