Image caption Michael and Cathy are still keeping us guessing

You might not expect a sitcom about a grieving widow's love life to be the brainchild of a man under 40 but BBC Two's Mum isn't your usual comedy drama.

As the third - and final - series goes to air, writer Stefan Golaszewski says age wasn't a barrier to creating the Bafta-winning series.

"I'm 38, the age thing doesn't really matter, or gender... things like race, religion, sexuality, they're all just the circumstances - what I'm interested in is the individual," he says.

The subtle comedy revolves around the life of suburban mum Cathy (Phantom Thread's Lesley Manville) as she grieves for her recently deceased husband and subsequently embarks on a will-they-won't-they relationship with family friend Michael (Tyrannosaur's Peter Mullan).

"What interested me was the things Cathy's going through - the experiences of women, the societal expectation of them, it's so much more demanding," says Golaszewski, who also created BBC Three sitcom Him & Her.

Image caption Cathy (left) has the patience of a saint with son Jason and girlfriend Kelly (centre)

"That creates immediate tension in the character. Cathy's story is a search for freedom and individuality."

Cathy is certainly the put-upon traditional mum, who is often taken for granted by her nearest and dearest - not least her son Jason (Sam Swainsbury) and his girlfriend Kelly (Lisa McGrillis), who are infuriating and hysterical in equal measure.

Manville invites the viewer to peel back the layers and discover there's a lot more to Cathy than meets the eye.

"She's very patient and non-judgemental with a huge sense of humour and a twinkle," Manville says.

She was attracted to the part by Cathy's story, which the Oscar-nominated actress describes as "a quiet unravelling... there's not a lot said".

Golaszewski's sparse dialogue is the result of a painstaking exercise, he explains.

Image caption Pauline - the ultimate social climber

"I know the narrative... then I just start writing quite quickly... then it's a process of rewriting... until it doesn't look like it's written, it's just people chatting. The words are just part of the setting, like the costumes etc. [I want] to have as few [words] as possible."

The role has found Manville a new audience, as she was previously best known for her theatre career and film collaborations with Mike Leigh.

"I get clocked for Mum more than anything. The response is always quite gentle. It's been quite remarkable," she says.

"It's a story about middle-aged people falling in love and looking like teenagers and that's not dealt with very much. It's real, normal, unglamorous. It's very refreshing."

Mullan, who recently starred in Ozark, also applauds Golaszewski's writing: "Film and TV are almost indistinguishable now, technically and in terms of the audience. When the writing's as strong as this, obviously you say yes."

The first two series of Mum each chronicled a year, with the drama taking place in the family home in Chingford.

Image caption Manville says Mum has become "very close to my heart"

Golaszewski says this "seemed appropriate with what she [Cathy] was going through [following her husband's death]".

But it's all change for the final series, with the action taking place as the family - plus Michael - gather at a fancy holiday home hired by Cathy's snobby sister-in-law Pauline (played by Dorothy Atkinson).

And this time, the season charts the events of just one week.

"It required a shorter timeline," Golaszewski says.

"The journey Cathy goes on would be harder to go on in her house, with ghosts in every corner."

That journey is the tentative yet tender relationship that has developed between Cathy and Michael and Manville says it's had an emotional impact on the actors as well as the audience.

"In series two, when Michael comes in to tell Cathy his mother's died... it was hard for all of us, you get drawn in... Peter was so heartbreaking in that moment, you can't help it.

"It's been a big deal this job. It feels very significant because of all the ingredients being so good, the writing, directing... and extraordinary actors. That cocktail is quite rare," Manville says.

"It's part of a great wave of comedy. I think it's just a great time we're in. How great to make you laugh one minute and cry the next. It's very close to my heart."

The quiet, slow-burning BBC Two sitcom Mum may be about to shout a bit louder - this weekend, the series is nominated for three Baftas, having picked up a Bafta Craft award for best comedy writing in 2017.

Whether it wins or not, fans will be sad to see the series draw to a conclusion.

Being careful not to give anything away, Mullan says: "I think it finishes as it should. The ending felt very natural, not forced or contrived, it doesn't tie everything up."

Manville concurs: "There's a feeling that life goes on."

The first episode of series three of Mum will air on Wednesday 15 May at 22:00 BST on BBC Two.

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