Call the Midwife: Will Barbara and Tom return in series seven?

He was talking about more than a day trip, because Poplar's most popular curate had been asked to take over a church called Saint Dionysius for six months while the vicar was ill. He wasn't exactly enthusiastic. "I know I'm supposed to go where God calls me," he sighed. "I just don't know why he would call me away from here."

Still, God called – so Tom took the job as a curate in Birmingham and off he and Barbara went on their new adventure.

Will Barbara and Tom be back in series seven of Call the Midwife?

Yes – but not until later in the series. "It's just sort of towards the end, the last few episodes, that we sneak back in," Ritchie explained at a screening in London before Christmas.

Why does Tom decide to take the job – and why does Barbara go with him?

"We're married. And in those days you go where your husband goes!" Ritchie joked. "No, that's not totally true.

"Basically, he has this opportunity to take a different job and discover a new parish, and I think it's a great opportunity for him, and we know it's possibly only temporary.

"It's a new adventure for us, so I go up with him... where he goes, I go, and where I go he goes."

Will Barbara return as a midwife?

Before she leaves, we do see Barbara have a vital discussion with Sister Julienne (Jenny Agutter).

"Will you still need me when I come back?" she asks.

Luckily, the answer is yes: Nurse Barbara's career as a midwife is not over yet. "Nonnatus House will always need good midwives," Sister Julienne says, adding: "And we will always need each other. Little matters more in such a fractured world."

Call the Midwife airs on Sundays at 8pm on BBC1