Image caption Lesley Manville stars in Mum as the widowed Cathy

Stefan Golaszewski has written two of the BBC's best-received sitcoms of recent years. Him & Her took viewers into the lives of 20-somethings Steve and Becky in their cramped flat in London.

Mum - starring Oscar nominee Lesley Manville (Phantom Thread) - is pulling in viewers with its painfully tentative romance between recently widowed Cathy and old friend Michael.

Golaszewski says an ambition is to change the way female characters are written on screen.

He grew up in Chingford in London's north-eastern suburbs. So far, his work has strayed from there only rarely.

Until its final series, Him & Her didn't move from the small flat the central characters shared in Walthamstow. The first two series of Mum have been set nearby, in leafier Chingford (though the show's exteriors are actually filmed in Croxley Green in Hertfordshire).

At 37, Golaszewski has now become a Hertfordshire resident himself, moving recently to Harpenden with his wife and two small children.

Golaszewski says he's often frustrated at how TV portrays female characters.

Image copyright Big Talk/BBC Image caption Him & Her: The character of Becky demonstrated a different female attitude to sex

"After Him & Her four years ago I wrote a few other bits and pieces but I came back to the sitcom again. As a structure and a format it can contain a great deal of popular appeal. But by the nature of the subjects you explore it has the capacity for depth too.

"When I first started writing Him & Her I was interested in the structure of each episode but nowadays with Mum I'm more caught up in the structure of the whole series. I'm finding the longer arc much more interesting.

"One of the ideas behind Mum was that I think the way TV - and society generally - presents and regards women over a certain age didn't seem truthful. I wanted to look at someone who's reaching a stage in life where our culture would probably regard them as washed up. But why should they be?

"It's always bothered me and, in a different way, it was also there in the Becky character in Him & Her (played by Sarah Solemani).

"Becky was my deliberate attempt to portray a young woman who was sexually interested through desire not need. She has an active will which is in no way problematic. In fact it was often her boyfriend Steve (Russell Tovey) who could appear the less confident one. I was trying to undermine the traditional way that relationship might be written."

Golaszewski says Mum (already recommissioned for its third and final series) tries to be realistic about falling in love.

Image copyright Universal Image caption Lesley Manville in Phantom Thread - Stefan Golaszewski admired her film performances before Mum

"Whenever you watch a film or a drama, the truth is often short-changed essentially for the sake of plot. On screen people fall in love incredibly easily and incredibly quickly. Actually it's terribly difficult. But I'm interested in the minutiae of falling in love: I wanted to watch it happen in a glacial way."

He says he always wanted Manville in the role of the woman who loses her husband in her 50s. "I'd seen Lesley in the film Another Year (written and directed by Mike Leigh) and I was completely bowled over. When Lesley said yes we were able to build our superb cast around her. I know it's a cliche but while we're filming it's like we're a family."

Most of the humour in the series doesn't come directly from Cathy or from Michael (played by Peter Mullan): there's a lurking tragedy in the way they seem incapable of expressing their powerful desire for one another. So far Cathy has stoically accepted her family's apparent blindness to her need for love.

But Golaszewski says he always bears in mind the audience's expectations of comedy too.

Image copyright Angel Media Image caption Stefan Golaszewski (right) acted in the BBC Three comedy Cowards (2009), which he also wrote

"So some of Mum's other characters are deliberately written larger. You have the grandparents (played by Karl Johnson and Marlene Sidaway) who may show an edge of the grotesque. But as the story progresses I hope I explain the roots of some of the behaviour you see on screen."

He also had another specific ambition with Mum. "I really wanted to explore the relationship between a woman and her daughter-in-law. It's such a basic part of family life and a really interesting dynamic. But hardly anyone writes about it.

"For me it's important that my writing is about kindness and understanding. It's about the nuance of togetherness and not separation. I'm writing about things that bring us together."

Half way through the arc of Mum, Golaszewski is keeping silent about what will happen in the final series, which he's busy writing. "I sit down at nine to write, then go out and get some exercise at lunchtime. Then I write again until about 5.30. And I don't write at the weekends or bank holidays."

With the final series of Him & Her he took the radical step of dropping the characters into a totally new situation - a hellish but utterly hilarious wedding ceremony with its chaotic build-up. But is he aware that with Mum some viewers are by now getting close to shouting at Cathy and Michael to get it together before it's all too late and the series ends?

Image caption Stefan Golaszewski also directed Mum

"I lead a relatively hermetically sealed existence at home with my wife and kids. I'm always surprised to find anyone's watching at all. The cast is more recognisable of course and after series one they told me anecdotes about things people would say in the street. But you have to write what's in your own head."

Golaszewski has also directed the current series of Mum. He says the BBC have been supportive in letting him pursue his vision. "We were allowed to make a pilot episode of Mum, which is getting rare. I had a basic feeling where each of the characters will go and what the show is about. But a lot of the detail comes in the writing: I make notes in my phone as I'm walking about.

"When I wrote the first series of Him & Her I was 28. It was the first thing I'd written for telly and it was only by series three and four that I was starting to know which buttons to push. So now I don't panic so much if I find I can't do it. Some days I will look at what I wrote the day before and maybe I thought it was great but I realise it's terrible.

"In fact the reason something is unworkable is often what made it appear attractive in the first place. As a writer you can be seduced by concept. But concepts aren't very useful when you're trying to write the truth about human beings."

Mum is on BBC Two on Tuesdays and is also available on BBC iPlayer.

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