After getting to watch and experience the on-set atmosphere for a while we get to sit down with Rundle and her castmates, including Danny Sapani (Black Panther), Serena Manteghi (Mrs Wilson), Steven Cree (Outlander), Dylan Brady (Ralph & Katie), Isak Férriz and Philipp Boos, to talk about The Diplomat.

All of them prove fascinating, warm and deeply passionate about the project, and none more so than Rundle.

She says: “I really wanted to come out to Barcelona – obviously, I then read the scripts and they’re so much fun. And I really liked Laura, I think she’s a really well-drawn character. I really recognised her as a woman.

“I know women like her, I went to school with women like her. And I really liked the thriller element of it, the mystery element of it. So I just thought, ‘Yes, please’.”

The Diplomat follows Rundle’s character Laura, who works at the British Consulate in Barcelona with her colleagues Alba (Manteghi), Carl (Brady), and new boss Sam (Cree).

Laura spends her time looking to help distressed British nationals while they’re in the Spanish city, sorting out issues surrounding lost passports, muggings, abductions, domestic violence and everything in between.

While the team encounter new cases of distressed British nationals each week, they also deal with the long-running storyline of the death of young British man Jay, after his father Colin (Sapani) casts doubt on the aspersion that it was caused by a fatal accident.

Rundle says of Laura: “She has this great line, she says, ‘You meet people at an extraordinary time in their lives, and then they leave and the rest of their story plays out elsewhere’. And that’s the central tenet to her job, really, she meets people in crisis, and then she doesn’t see them again.

“And then I think with Colin, she’s used to dealing with this kind of scenario, but she comes to realise that she just really quite likes Colin. I think she has a huge capacity for empathy and compassion, which is why she does this job, but I think she sort of roots for him.”

She continues: “So when he starts saying ‘something’s not right’, she’s used to people saying that, because people do, but actually she listens to him and she’s on his side. And she feels like she needs to fight for him.”

A great number of Rundle’s scenes across the series are alongside Manteghi, with Rundle praising the show’s presentation of female friendship.

She says: “I love Serena’s character Alba and I really liked the dynamic between them. Because I think it’s still quite unusual to get to see our female characters just being funny, outside of a comedy show.

“To get to see women being witty with each other and quick and enjoying each other’s company. And I really love that element of it, that lightness and that brevity, and the humour in amongst it.”

Manteghi describes Alba and Laura’ friendship as a “meeting of souls”, explaining: “Alba and Laura are very much an odd couple but almost because of that they’re extremely close. They seem to really respect and love each other because of how different they are.

“I think Alba is just astounded by someone who can be, on paper, everything that Alba would not like – very competent, very professional, very diplomatic, all these things that Alba really isn’t naturally. But then also not pretentious or frosty or intimidating. Laura is very accessible, very on a level and very dry-humoured.”

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Alongside its glorious setting, perhaps the thing which is most notable about The Diplomat is its tone, something which Manteghi calls “The Office meets Bodyguard”.

Brady agrees: “I’m so glad you said it. There are moments where we’re in a take and I just crack because I’m like, ‘This is funny’. And the stakes are high and it is gritty, and it covers some really great ground in terms of the topics it explores, and some of it’s pretty hard hitting. But the whole thing is actually three mates, and sometimes it’s really f**king funny.”

Doing a lot of the dramatic heavy lifting is Sapani, as grieving father Colin. He came to the series after working with this show’s director Jill Robertson on 2017-18 series Harlots.

Sapani explains what drew him to the role, saying: “I really liked the script. I thought it was quite sort of unusual. It’s not a detective story – it sort of falls into this gap where stories can happen.”

It’s true – The Diplomat is a new twist on the crime drama, in that by not following a detective or police officer, it looks at the events from a different perspective.

It also gives us a look into a world which is unknown to most people, with Sapani saying he knew “absolutely nothing” about the role of the consulate before coming on board.

“I’m very fortunate that I’ve never had to call upon the consul in any country that I’ve been to,” he says. “But yeah, it’s an eye-opener.

“And I think for a lot of people, this will be like, ‘Oh, right. Very interesting. This is what they do and this is going on all the time.’ I think it’d probably be quite a good formula. You could probably have one in each country in the world.”

Wrapped up in the case of Jay’s death are Sam, Laura’s new boss who seems to want it swept under the carpet, Inspector Castells (Férriz), the investigating officer on the case, and Fabian Hartmann (Boos), a businessman who was Jay’s employer.

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Boos, a trilingual German actor who only started acting five years ago at the age of 35, says getting the role is the “best thing that’s happened” to him and a “big opportunity”.

“I mean, speaking three languages [his character is also trilingual], working with these great actors – it’s really great, for me it’s a big, big opportunity.” says Boos. “There was no choice, for me it was, ‘Yes. I want this.’”

Cree is similarly hugely positive about the experience, explaining: “You don’t love every job you do, I think that’s the same for everyone. A lot of people don’t love their job ever, but in acting, I think because acting is vocational for a lot of people, you almost expect or hope that you do, because it’s so hard to getting work.

“Even when things are going well, it can still be hard to get jobs. In fact, even harder in a strange way because you want to wait for the good ones. And so when you do then get them you want it to be really good. And it’s just not always the way it is. You don’t always get on with the cast as well, or everyone doesn’t gel, or it’s not such an amazing location.

“But this has been, every aspect of it. I’ve loved the character, I’ve loved the scripts, the cast, we all get on fantastically well, everyone’s lovely. And Barcelona is amazing.”

He particularly praises his character Sam’s development across the six episodes, saying: “I love the direction and the journey that they’ve taken Sam on. Sam arrives in episode 1 as the new Consul General of the British Consulate, but then we almost immediately discover that all is not exactly what it seems with Sam. Is he a good guy, is he a bad guy?

“It’s brilliant to play. It’s always great to play somebody with a secret, where the audience know there’s a secret, but they don’t know what it is. The other actors in this didn’t know who I was either in the first few days of filming. They were like, ‘So what is it that you’re doing?’”

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Meanwhile Férriz, a native of Barcelona, thinks audiences will learn a lot about the city from watching this series. “We are running away from the typical postcard of Barcelona”, he says. “I think we are running away from the folkloric image that we all have of Spain, and Catalan.”

That’s certainly the case for Rundle, who has loved her time working in the city. She says: “March 2020 the world got very small for a while, and then they said, ‘Do you want to come out here and do this’ and it’s like the world’s opened back up again. It’s been such a breath of fresh air.

“It’s one thing getting to come and visit Barcelona for a holiday, but to get to come and work out here, it’s been joyful. It’s been such an amazing experience. I feel really lucky.”

Six months later in January 2023 and we’re sitting down to watch the first episode of The Diplomat at a screening in Battersea Power Station. As soon as the titles roll, I’m transported back to that brief period I spent in sunny Barcelona, and feel sure that viewers will feel similarly enrapt by the series’ setting and aesthetic.

Whether they are will of course determine whether we see more from The Diplomat. While on set, Rundle said that it “totally could continue”, before adding: “Whether it does or not, who knows, because TV is crazy at the moment.”

She continued: “It totally has the potential to go in all different directions. It has this huge international reach and appeal, and it’s such a clever format. We’re very used to seeing procedural dramas, I don’t really know why no one’s ever thought to do this before. So it has a huge capacity to keep going.”