Call The Midwife shares advance look at series 10 premiere featuring star Helen George

The opener will focus on a pitch to introduce a private clinic to Nonnatus House, a move that would give the convent a much-needed financial boost, but the idea isn't without its detractors.

In fact, Dr Turner (Stephen McGann) is vehemently opposed to the principle of private healthcare and this drives a wedge between himself and Sister Julienne (Jenny Agutter) for the first time in two decades.

However, for Trixie, it's an exciting prospect that allows her to go on a trip to a clinic in Chelsea and learn about their alternate methods of delivering babies.

Helen George herself introduces and commentates over new footage from series ten in this advance clip, which was shared to the official Call The Midwife Twitter page.

"Episode one is very exciting for Trixie," says George. "She gets to go to the Lady Emily Clinic, which is a private clinic in Chelsea, to observe exactly how their systems work and how the midwifery is in place.

"The thought is that Nonnatus House will rent out midwives and nuns to the Lady Emily to help out, to staff the clinic, and in return they'll get a monetary fund so that Nonnatus House is saved."

Almost a decade since its debut, Call The Midwife remains one of the most popular shows on British television, with last year's festive special earning the highest live viewership of any programme on Christmas Day (excluding the Queen's Speech) – a total of 5.4 million tuned in.

Call The Midwife remains such a ratings juggernaut that the show has been renewed for an additional two series, which were announced by the BBC earlier this week.

Call The Midwife series 10 premieres on Sunday 18th April at 8pm on BBC One. Check out more of our Drama coverage or visit our TV Guide to see what's on tonight.