Being Human really shouldn't have happened. A preposterous idea, an epic and circuitous development process, a modest budget - no, we really shouldn't have lasted. But Being Human was the little show that could, and that ridiculous idea managed to last 37 episodes, spawn an American version, three novels, an online spin-off, and garner a shelf of awards.

But Being Human was always a collective effort, and none of that would have happened if it weren't for five separate groups of people.

First, the various producers and execs and script editors. Rob Pursey, Matt Bouch, Phil Trethowan, Polly Buckle, and Laura Cotton. Every idea I had was enhanced, improved, enlarged, and enabled by their brilliance and creativity.

Then there are the numerous writers and directors who have had to endure my capriciousness, vagueness, indecisiveness, and propensity to steal their best ideas and pass them off as my own.

It's also given me the chance to work with - and write for - some of the finest actors working today. Russell Tovey, Lenora Crichlow, Aiden Turner, Sinead Keenan, Jason Watkins, Michael Socha, Kate Bracken and Damien Molony. Looking at that list again now, I'm staggered by its ferocious talent and brilliance.

And I have to thank the BBC. Not because I'm obliged to, but because I literally have to. They gave us the opportunity to make Being Human and to make it in the way we wanted. Julie Gardner, Ben Stephenson, Danny Cohen, Beth Willis, Brian Minchin, Eleanor Moran, George Ormond, and Zai Bennett were unwavering in their support, guidance, trust, love, and enthusiasm, and gave us - and me specifically - an unprecedented level of creative latitude. For that I will always be grateful.

And finally - and most importantly - the fans.

I know many of them will be disappointed that the show isn't returning, but all good things come to an end.

We must remember too that the remit of BBC Three is to encourage and support new talent, to give them opportunities to make television, to test out new ideas and formats. In that sense, Being Human is perhaps a victim of its own success. We can't really call ourselves a new show any more, and much as I'd like to think of myself as a young, thrusting, new talent and not a bitter old war horse, the reality is we have a duty to move aside and make space for the next Being Human.

But much like the cast change from seasons 3 to 4, we viewed the news as an opportunity. It meant I could actually write a climax for the show, instead of it just popping out to the shops at the end of season 5 and never coming back. You've no idea how rare that is in television, and what a great opportunity it is to write something suitably definitive and satisfactory.

Consequently, we've created what I hope you'll agree is an epic, thrilling, and shocking finale that'll keep the fans guessing and speculating for years to come.

Then Being Human will belong to them. Once the credits on episode 6 roll, the future of all those characters will exist in the imagination of the audience, to do with as they please. But in a way, the show always did belong to the fans. Their tenacity, passion, and loyalty are what kept the show going and provided inspiration to everyone working on it.

I'm reminded of the scene in series 3, episode 8, with Mitchell and Herrick sitting in the car looking at the sunset. Herrick asks if Mitchell finds it amazing that soon this world will be theirs. And Mitchell says: "It always was."

(Yeah, and then he stakes him, I know. Ignore that bit.)

Working on Being Human has been a truly great experience. From the first one-hour pilot, all the way through to this climactic series, we've been given real creative freedom and encouragement. It's a credit to BBC Three that such an unusual idea has been allowed to flourish and evolve in its own unique way.

I'd like to take the chance to thank Toby Whithouse for his incredible writing and storytelling; the other screenwriters who've made the series their own; the three producers who've nurtured the show; and the many directors who've helped us establish the show's unique tone. Being Human has also opened the door to new acting talent, including some incredibly exciting younger actors, which is a legacy we all feel proud of. We will miss Being Human, but feel inspired that there is a place for series like this on British television.

Being Human has been a fantastic and faithful friend to BBC Three. It's featured some truly exceptional actors and storylines through the years and I'd like to thank Toby and the production team for their vision and passion. However, all good things come to an end and at BBC Three we're committed to breaking new shows and new talent and who better to pass that baton on than Toby?

Alex discovers she's not the only ghost haunting Honolulu Heights. Meanwhile, Tom and Hal go head-to-head in the hotel's Employee of the Month competition, much to the delight of Captain Hatch, who feeds on werewolf/vampire conflict. In the supernatural archive, Mr Rook is hatching a devious scheme to save his department: one that involves newly-made vampire Crumb.

Thunderbirds Are Go! will be a hugely exciting new show for the CITV audience. We're delighted to be working with ITV Studios and the talented teams at Pukeko Pictures and Weta Workshop, whose success and innovation is renowned across the film and television industry. Thunderbirds is a much-loved British institution with significant global recognition, and our audience will relish this timely opportunity to discover the new series 50 years on.

Thunderbirds is a highly-respected brand that continues to hold recognition around the world. This cult series is often credited as changing the history of animation and action-adventure, and we look forward to taking the show to another level while retaining the much-loved heritage that has endured over the past 50 years.

Thunderbirds was a hugely influential television series in my childhood. Having watched it originally in black and white, it was only years later that I discovered the full and rich world that Gerry and Sylvia Anderson, Derek Meddings, Mike Trimm, and their team created. It is thrilling, therefore, to think we have the opportunity to work with ITV on this new series inspired by this most wonderful of British shows.

I personally, together with the teams here at Pukeko Pictures and Weta Workshop, look forward to designing and creating an inspirational world that will engage the imagination of a whole new generation as it did for us nearly half a century ago.

Pukeko Pictures is focused on high-quality value-based programming, and we are thrilled to be associated with such an iconic brand, one that brilliantly encompasses family values, heroism, and generosity. We are very proud to partner with ITV Studios to create a new era of Thunderbirds.