Poignant is a word that doesn’t get used much these days, but it fits Mum (BBC Two) like a glove. In this spare, quiet sitcom, deep emotions aren’t so much plumbed as plucked at in a piquant, reserved, achingly sympathetic way.

Lesley Manville plays widowed Cathy, who is trying to hold on to her sense of self in the wake of her husband’s death. She is a loving, endlessly maternal woman to whom everyone in her dysfunctional family still turns for support, despite the bottom falling out of her own world. Not the most promising scenario for a sitcom, perhaps, but it works, beautifully. So it was no surprise that its writer, Stefan Golaszewski, won a Bafta for the series’ pitch-perfect debut, which juggled laughs and sharp emotional insight with a sure comic touch, and Manville was also nominated for her sublime performance.

As the second series began, Cathy had another soul-sapping challenge to confront: her 60th birthday,

Again, the laugh-out-loud moments were provided by Cathy’s nice-but-dim son Jason (Sam Swainsbury) and his amoeba-brained girlfriend Kelly (Lisa McGrillis), with occasional bombs dropped by her aggressively senile father-in-law Reg (Karl Johnson) and unrepentantly snobbish sister-in-law Pauline (Dorothy Atkinson). Yet the really biting, bittersweet comedy moments all revolved around Cathy. Not so much in what happened or what she said, but in what failed to happen and what remained steadfastly unsaid.