Video: Behind the scenes at Sky

Writer, director and co-producer Gary Russell said: "There's a golden decade of kids' TV between 1972 and 1982, much of it produced by HTV and Patrick Dromgoole, often written by Bob Baker and Dave Martin. One of those gems was Sky, a show that displayed an intelligence and sophistication that many other ITV companies tried to emulate, but rarely did.

"The ultimate outsider, Sky was neither good nor evil, neither a hero nor a villain. The same goes for the other characters around him: Arby, Goodchild, the Briggs family – there are marvellous moral ambiguities about all of them. 

"I love the original; it was a show I had grown up on and seen a thousand times, because I've got it on a nice shiny disc. Jason Haigh-Ellery turned around to me one day and said, 'Look, we've got the rights from Bob Baker to do a new version of Sky.' I think he could see the passion and fervour and begging in my eyes. He said, 'Do you want to do it?', and I said yes, because I knew exactly what I wanted to do with it. I'd been thinking since 1975 about what you could do with this show, so I was very keen to sit down and get on with it.

"Jason said to me, 'Do you want to do a remake?', and I said 'No, I want to do a sequel.' I wanted to pick the story up 50 years later, and therefore I knew that the only character I needed to bring back – other than Sky, obviously – was Arby. The idea of Arby, the hero of the original, being this broken old man sitting in a nursing home somewhere – I thought, that’s your good launch pad. It's about a redemption for him."

"To be asked to find out what happened next, and the effect Sky's parting gift to Arby might have on a human, was too good an offer to say no to. I love these characters passionately and it's a joy to be able to tell these latest chapters in their lives – the first audio serial I've ever written for Big Finish."

His co-producer Dominic G. Martin added: "The tale of Sky is an absolute belter of a story! I was born long after it aired, and despite growing up on a lot of classic TV, I only learned about Sky from Gary Russell. Hearing that Bob Baker and Dave Martin were the original serial's writers made me instantly excited to get involved.

"It's a such a fascinating concept that you could pull off in any era with all its mysteries and dynamic characters. The whole cast was magnificent in the recordings – they were such a delight to work with, and I would love to think that the new series is not only a loving tribute to the work of Baker and Martin, but also builds on that grand story that they set up back in the 1970s, while keeping it accessible for a whole new generation to get immersed in."

Lead actor Cloud Quinn takes over the role played by Marc Harrison in the original TV series. He said: "Sky definitely piqued my interest. I watched a little on YouTube and I read the novel of the original 1970 series, and I just loved the imagination of it.

"It felt very challenging for children, but in a good way, opening their horizons to the big issues of the day around space flight and nuclear power and continuous industrialisation, and what that meant for the natural world – obviously that remains very, very relevant today.

Edwin Flay, who plays Arby Vennor, added: "The audio revival is very well crafted in that you don’t need to have seen the original, but it grows from it, it feeds on it, and it brings all of the concerns very much up to date. The way our two characters have evolved from the original series and the journeys they’ve been on in the interim give it a lot of its meat for me, certainly.

"In the original series, Arby Vennor was young, vibrant, and kind – a very straightforward, uncomplicated character – and now his experience has left him a broken shell. Exploring that, as he finds his drive and his sense of self again, has been a pleasure."

Conrad Westmaas, Rachel Handshaw, Caitlyn Galvin, Tara Ward

Jessica Hayles, Cloud Quinn, Edwin Flay, Samuel Morgan-Davies

Cloud Quinn