David Tennant is mulling over his latest accolade.

The Broadchurch star has been crowned the UK's hardest working actor; a title he accrued in a study of 100 prolific television and film stars, including the likes of Martin Clunes, Dame Judi Dench and his former co-star Olivia Colman.

Not that he's entirely convinced of his victory.

"What was the criteria? I am slightly mystified - as opposed to what?" he asks, chuckling at the BritBox-led review. "Surely someone who is on EastEnders works harder than I do?

"But I'm very glad to be working at all times; I always feel like it's a privilege to be able to make a living as an actor, as it always feels like at any moment, that might stop," he admits.

"Maybe that's just the freelance mindset? But I think you're only as good as the last thing you managed to achieve. So, while I don't really know what [the title] means, I'll take any accolade, frankly!"

Characteristically modest, maybe. But it's far from the first time his efforts have been rewarded, with Tennant, 48, scooping everything from a Bafta for this revered time as the Tenth Doctor in Doctor Who; to a Daytime Emmy Award for his work on animated American TV series, Star Wars: Clone Wars.

He even landed a special recognition at the National Television Awards in 2015 - a surprise win that he went on to dedicate to his father and "the talented and clever people who gave me a job".

Fast-forward five years and the Scottish actor, who began his TV career in children's show Dramarama in 1988, hasn't stopped. As his most recent accomplishment would suggest.

His latest outing comes in the form of Deadwater Fell; a tricky-to-sum-up four-part drama - penned by Grantchester writer Daisy Coulam - about a small community rocked by a heinous crime.

When a seemingly perfect and happy family is murdered by someone they know and trust, the small Scottish community they call home becomes riven with suspicion, as those closest to them begin to question everything they thought they knew about their friends, the Channel 4 synopsis reads.

"We present very different versions of ourselves in public and in private," Tennant offers, taking in the premise. "Nobody really knows what's going on behind the net curtains."

Yet it's hard to define in terms of genre, he insists.

"It was hard to pin down: it was a thriller, but it wasn't a thriller. These characters were so vivid and yet slightly slipped through your fingers as well.

"There's something about the way Daisy wrote the first episode, which was unlike anything else really," adds Tennant, who brilliantly portrays Tom Kendrick, a local GP and the father of the tragic family.

"It had the trappings of a thriller, but it was something more than that, something more subtle and odd than that. It was just compelling; it keeps upsetting your expectations."

Of its whodunit set up, he follows: "When you read the script for the first time, it's the closest you will get to the experience that the audience will have.

"So, if I enjoyed this, if I turned the pages, then you can presume hopefully that an audience will be confounded and surprised and bewildered like I was."

"Daisy keeps taking the floor away from under you, just when you think you figured out who these characters are," he warns.

Did the dark scenes - and they get pretty dark - leave him needing to decompress?

"You try and get the emotional beats as accurate as you can, and you draw on personal experience, however remote that might be," recognises the father-of-five. "But the rest of it is an imaginative leap, as mercifully, I've not suffered the desperate tragedies that Tom suffers.

"I've never consciously felt emotionally scarred by playing any part," he confides. "Sometimes things are a slower burn, but there's an exorcism in seeing someone else's emotional reaction to things - that, in itself, is a form of therapy.

"I suppose it's one of the reasons people like to act, because it's about walking in others' shoes," he muses.

"You do have to go to some dark places sometimes, but then there's always the moment when they say, 'Cut' - and you realise you're not actually there, which can be quite life-affirming."

But Tennant is well-versed in the intensity of TV crime drama - and, coincidentally, medicine - as we last saw him playing a chilling doctor suspected of murder in Netflix's Criminal.

Not that he seeks out recurring themes, he's keen to stress: "Criminal was a completely different experience and yet there are also similarities, but I don't think tactically or make objective choices about linking parts up.

"I respond to things that feel different to things I've done before, but I've never felt limited to one genre," he continues. "I feel like I've been quite lucky to get to do kids' animations and then something like this, and then a Marvel thing and then a family movie...

"It's other people who go, 'Oh, that's a bit like that other thing you did', but an actor is vain enough to believe they transform themselves every time, and they're unrecognisable from part to part!"

Talking of switching things up, Deadwater Fell also sees Tennant tick off his first executive producer credit.

"It presented itself as an opportunity, and I thought, 'Well, why not?' It would be fascinating to see if I had anything to offer in that role, frankly," he says with a smile.

"I was just kneeling at the feet of the experts and learning how it all works. It was great. I was delighted to be able to be involved at an earlier stage than actors often are.

"Whether I brought much to or not, I don't know, but I certainly enjoyed being in some of that."

And going forward? "I'd like to be involved in that way, if it was appropriate," says Tennant, who has recently been cast to play serial killer Dennis Nilsen in upcoming ITV drama, Des.

"But I'm not currently looking to develop things from scratch myself - there are people who are better at that than I am, and one has to be aware of one's own skill set.

"I would much rather be involved in helping to make real something that someone with those sorts of talents can come up with," he elaborates. "I'm looking to be inspired by someone else's brilliance - rather than sit at home going, 'Right, what's my next job...'

"I don't think I'm quite there yet, but never say never!"

Deadwater Fells starts on Channel 4 on Friday, 9pm.