Where do we find Hannah at the start of series three? We know her divorce from Nathan is looming...
We find her in the midst of the divorce, but specifically at the end of a working day she’s getting ready to go and meet him for dinner, so she’s quite hopeful. Admittedly, the dinner is a meeting of school parents (her daughter Liv has been away on a gap year) so this is one of those last meals with vague parent friends. But Hannah is hopeful, there’s still everything to play for.

There’s a new arrival from Kate, who complicates that relationship with Hannah and Nathan. How does Hannah react to Kate being a potential love interest for Nathan?

It’s one of the most horrific meal scenes I’ve ever read! There’s a great history of difficult dinners in drama, this is one of the greats. Abi has put Hannah in possibly one of the most excruciating positions any person could find themselves in - when Hannah meets Kate she didn’t realise that Nathan was seeing somebody. The cherry on the cake is that Kate is incredibly successful, intelligent, beautiful and a great deal younger, and all of this revelation takes place while trying to eat food with chopsticks, which I think is a beautiful touch from Abi Morgan!

Thankfully myself and Lara have known each other for a long time. I was really overjoyed when it was Lara who was cast as Kate, we worked together years back on Spooks, and she’s one of the most delightful human beings. So, it was wonderful to have that prior relationship because then we could give full vent to the pain in the show between the two of us. At the end of really awkward takes, we would both run up and cling to each other and laugh and say "I love you, I really love you!"

To further complicate life for Hannah there’s the return of Christie as well...

On a practical level, because of Covid, we were concerned that we wouldn’t get Barry Atsma back! But fortunately, the clouds parted so Christie does return. It’s so important that Christie comes back as that story needed to continue in some way, because it’s always been there for Hannah. It’s not that it complicates things because it’s always been complicated with Christie, but it offers an option for Hannah.

Can you talk through the big legal case for this series, and the issues explored there?

This case is a really complicated one, about the right to have control of your end-of-life care. Hannah knows Lennie because she is Zander’s sister, and when she arrives to ask for a divorce, initially Hannah laughs because Lennie has this fantastic marriage that Hannah knows is rock solid, so there must be something else going on.

It allows Abi to talk about ‘what does marriage really mean? What does love, what does commitment really mean?’ And that’s what the show’s always been about really. Abi has said from the beginning that’s the trojan horse; it’s a show about divorce that’s actually talking about love. This case is the perfect narrative to look at that.

A recurring theme is whether women can be perceived to ‘have it all’ - was it a joy to have that dealt with so honestly throughout The Split?

That awful phrase ‘have it all’! No-one can have it all, no man, no woman, no-one! I think Hannah’s got to the age where she’s way past believing in clichés like ‘having it all’. She’s worried about having it okay for her family and herself and for Nathan. She’s at a different stage in her life. Yes, she has a very successful career - it looked perfect from the outside in season one, didn't it - Pperfect marriage, perfect children!

But she’s no fool is Hannah, she knows that that doesn’t exist because of the people who come through her office door every day. What looks perfect on the outside, you scratch it and it’s all very complicated, irrespective of your economic bracket. Her job has taught her that and unfortunately her own life has taught her that over the three seasons. It’s not that Hannah’s become accepting of that, she’s getting up off the floor and thinking, okay, well how do you live with that? She navigates her way through it in a very grown-up and positive way. Not everything goes the way she thinks it will and not everything goes the way Nathan thinks it will. It’s very equal, the desire from both of them to make it work.

And this series, podcasts arrive at their law firm, Noble Hale Defoe!

Isn’t it fantastic! Our mother with her podcast! Of course that is what Ruth (Deborah Findlay) would do. You cannot keep that woman down. She’s always moving forward, got to keep going, keep swimming, so yes, she’s the one embracing the new tech! She’s perfect for a podcast.

What will you miss most about Hannah and The Split?

The clothes, the houses, being able to film in beautiful places in London, walking into amazing rooftop apartments! I will miss having a little peek into that world! The main thing is I’m going to miss getting to walk in Hannah’s shoes for four months of the year, and that is down to Abi creating this incredible family. I’m going to miss my imaginary, pretend Defoe family, very much.

It was very difficult filming the last few scenes with Deb (Finlay), Fiona (Button) and Bel (Scholey) because in between takes we were saying "that’s the last time I’m going to be your sister, or you’re going to be my mother". We’re feeling it very, very deeply! I’ve said to Stephen (Mangan), "no one is going to let us act together for a long time now!" on a practical level that’s what happens, you’re not really allowed to share a screen together for quite a while. I find that deeply upsetting I’m not going to get to hang out with Mangan and act with him. It’s very sad, but we had a great time!

And - no spoilers - but are you satisfied with the show’s ending?

Absolutely. Endings are difficult. I think Abi has managed to create a really satisfying ending, and we don’t get that in drama very much anymore. How many shows have we all watched over the pandemic where you’re left unsatisfied in the last 15 minutes? That doesn’t happen with this show. Abi has taken great care of every single character and I feel by the end that you know they’re going to go on. In my head, they’re all getting up and going on with their lives when the credits roll.