The funfair comes to Poplar, adding a burst of colour to the festive season, but there are other less welcome visitors to the borough, including Hong Kong flu and escaped prisoners.

It's March 1970. The team support a pregnant teenage girl whose parents believe in an immaculate conception. Demonstrations cause havoc for the Nonnatus team, whilst Nancy's relationship blossoms.

It's April 1970. Rising rates of gonorrhoea in the district cause alarm, and Trixie cares for an unmarried first-time mother recently diagnosed with a mental health condition.

Rosalind requires all her skills as a midwife when a disabled baby is delivered at the maternity home, whilst a gas explosion in an old tenement building shocks the community.

The sisters welcome a new postulant, Sister Catherine, to Nonnatus House, whilst a bold intervention boosts numbers for the measles vaccination clinic.

A solo delivery puts Sister Julienne's skills to the utmost test. The Nonnatus team oversee the care of a man living inside an iron lung, and Cyril returns from Jamaica.