Do X-Files fans still want to believe? The paranormal US drama series, which partnered Gillian Anderson’s sceptic Scully with David Duchovny’s more open-minded Mulder, was an intrinsic part of nineties pop culture. In its heyday, it could be terrifying, warmly funny – with that famous Anderson-Duchovny chemistry at its heart – and brilliantly bizarre, often all at once.

It came to a temporary end in 2002 after nine seasons, spawned a rather disappointing 2008 film, and then dramatically returned in 2016, along with its leads, for a six-part mini-series. The revival hit the right nostalgia buttons for hardcore fans and pulled in some impressive viewing figures, but also gained mixed to downright negative reviews. For some, this heavily anticipated comeback was a bit of a damp squib.

Undeterred by these attitudes, and bolstered by the undying affection of long-term viewers, The X-Files creator and writer-director Chris Carter and Fox went ahead with an 11th season, which begins in the UK on Monday 5 February.

This time, audiences can enjoy a full 10 episodes, with a satisfying medley of traditional “monster of the week” stories and long-running X-Files “mythology” material. In the US, where the new series started a few weeks ago, the response so far has been encouragingly positive. There has been some disheartening news too, however: Anderson has announced, and reiterated, that this will be her last-ever season.

Catching up with Carter ahead of the UK broadcast, he is uncertain about exactly what this might mean for The X-Files. “I don’t know,” he says, when we ask if the series could have a future without Anderson. “I don’t think it will be the same X-Files without Mulder and Scully together. Right now, this is uncharted territory and I’m going to wait until I hear what some other people think.”

The character of Dana Scully, of course, has always been a vital part of the success of the series. But in 2016, as issues surrounding equal pay hit the headlines, Anderson revealed that she had initially been offered only half the money that Duchovny was receiving for the revival. Annoyed that she had previously fought for equal pay in the nineties, only to face the same problem years later, she described the situation as “sad” and “shocking”.

Carter, perhaps controversially, thinks the significance of this story has been exaggerated. “I always thought that was an overblown issue,” he says, when I ask for his take on the pay offer.

“Simply, and I experience this myself, we work for a company that tries to make the best deal for themselves possible. So what they do to each of us is they try to get us to do it as cheaply as possible; that’s the business that they’re in. So while you can make the argument that what David makes, Gillian should make, the powers that be see this as transactional, contractional employment, and they try to conduct their business as such. While, on the face of it, it looks like they were paid differently, I’d see this as business as usual, as it’s always been for the last 25 years.”

“I’m happy to say now though that David and Gillian are paid exactly the same amount of money,” he adds.

Either way, Anderson’s decision to leave, as reported, had nothing to do with the now-resolved pay issue: the actress simply felt that it was time to bid goodbye to a character that she has played, on and off for over 25 years. The X-Files first made its debut in 1993 – and, thanks in part to its extended hiatus, it’s easy to think of its two most recent seasons as a sort of throwback; a nostalgic bone for the loyal rather than a significant modern-day television series.

But this would be unfair. With its focus on powerful conspiracies and the nebulous, hard-to-pin-down nature of truth, the new season has a decidedly 2018 feel to it. The rise of Donald Trump, a president who plays fast and loose with the facts and repeatedly gets away with it, has been a key influence – as has the advent of internet-driven “fake news”.

“The show has always been of its time, and of its political moment,” Carter says. “We’ve been through four presidencies on this show, and the latest one opens up new things to talk about, obviously. What’s very curious, and what’s radically different, is that there was "the truth" and "science" in the nineties, and that was the beating heart of the show. And now the truth has been marginalised and conspiracy theories have gone mainstream. And that is a significant difference and something that we certainly have something to say about.”

For its creator, in fact, The X-Files has never felt like an escapist science-fiction show. “I always resisted the label science fiction because I always thought of it as a science show. It was Scully, Scully’s science, that rules, and Mulder’s science fiction that took flight,” he explains. “We had two very interesting characters dealing with subjects, from two different points of view, that oftentimes were science fiction – and have oftentimes now become science fact. I think of cloning; I think of the latest revelation about the US government programme to investigate UFOs. I think these are interesting things that have validated the whole concept of the The X-Files.”

“Since I began doing this show, I pick up the paper every day and read and think ‘Oh, there’s an X file’,” he later adds. “Oftentimes they come from science, technology, things that scare us. They come from urban mythologies, urban legend. It’s exciting how many different places X files can come from.”

In keeping with this spirit, the new season has a clever Darin Morgan-scripted episode inspired by the Mandela delusion (the name given to a phenomenon whereby a disparate group of people share the same false memory, used by some as an argument for parallel universes). Another episode offers a dark, rather Black Mirror-like exploration of digital immortality.

Alongside these very modern themes, Carter has also used season 11 to pick up some of the show’s older mysteries. There’s a newly urgent focus on the mysterious William, who fans will remember as the long-lost son of Mulder and Scully – and the first episode contains a shattering reveal, relating to the character, that directly links back to an episode from 2000. Remarkably, Carter has been planning this twist (which we won’t outline here) for almost 18 years – without ever knowing if he’d get a chance to unveil it.

“It’s something that I’ve been thinking about for some time and it was important,” Carter says of the new development. “There are four episodes that bookend the two seasons – what we’re calling season 10 and season 11. And they all ultimately revolve around that fact, and around the mystery of this child. But I didn’t know the show would come back, so I didn’t know if I would get to continue with that storyline.”

Fans of The X-Files have always had passionate opinions about the mythology storylines – and will likely have a strong reaction to some of this season’s forthcoming developments. Is it scarier putting episodes out now, where the social media reaction can be instant and brutal, than it was back in 1993? Carter seems resigned.

“I think it’s a good thing, that we’re engaging people’s immediate reaction, and that they are engaged. I think sometimes, as we all know, there are people out there engaged in mischief. It’s the haters. And when I see that, and when I see a thread or I hear about one – because I’m not on social media myself, I have an Instagram account that I never use – that’s for me disappointing. But understandable in the world we live in.”

At 61, the writer-director and producer has spent four decades working in television, with The X-Files remaining his best-known, most enduring achievement. But he has previously spoken about the possibility of bringing back another of his series, the comparatively little-known Millennium, which ran on Fox between 1996 and 1999 and starred Lance Henriksen as a criminal profiler with the ability to see into the minds of his subjects.

The show, while critically acclaimed at the time, would be a much tougher sell than The X-Files, lacking as it does the large fanbase – but Carter believes that it could work. “I’m waiting for someone to ask. I’m ready for the powers-that-be to say ‘yeah we’d like to bring Millennium back!’,” he says. “Because I have ideas about how it could come back. I basically pulled the plug on the show, but I did it in its prime, I think. I think it died a death too soon – but I still think that it can be resurrected.”

After all, as he points out, we’re currently living in an age of reboots – with the shows and films being adapted often predating both Millennium and The X-Files. With the future of the revived X-Files looking extremely uncertain - and the latest season seemingly shaping up to be a success - perhaps it's time for another Carter comeback.