Although they have been working on the show since April, this will be the first chance they have had to see everything come together, and on-set camaraderie has given over to a first-night atmosphere of banter, leg-pulling and genuine pride in the work.

They’re not wrong. There’s a lot to like about this 21st century mash-up of the Greek myths.

Executive produced by the production team behind Merlin, and filling the same slot, it feels like lessons have been learned from the former show about just how to hit the ground running.

Jack Donnelly stars as Jason, the Greek hero of the same name – albeit one who has been gifted a back story of a missing father – and, for the bulk of this first episode, it’s his show. Within the first ten minutes, events have contrived to rob him of all his clothes, and there follows a series of action sequences as he stumbles into adventure: dodging arrows in slow-motion, back flipping to escape attack and, ultimately, enjoying a scene with Aiysha Hart’s Princess Ariadne that has probably as much erotic charge as you can get away with on a Saturday early evening.

It’s a warm-hearted and confident debut for a programme that promises to brighten up the autumn months – and not just with the Moroccan sunshine of the exterior sequences, lovingly recreated for many of the shots in a warehouse in Chepstow.

The episode, we are told, has been in the edit until late last night, but it’s a slick piece of work – not least in the CGI. The production team have started off big, and intend to get bigger. So the central myth that gets the revisionist treatment this episode is the story of Theseus – now Jason – and the Minotaur.

Expect a labyrinth and ball of string. But also expect the kind of humour and gentle piss-taking that characterised Merlin. When you have an actor like Robert Emms in the cast – an actor who was made to play a state of apologetic bewilderment – it’s unthinkable not to give him character comedy. And when you cast him as Pythagoras no less, it’s clear where the geek appeal is going to come from. Anybody who is quite so into triangles is, inevitably, going to be a little square, and the pairing of Donnelly’s buff heroics with Emms’s cerebral innocence is what gives the episode its driving dynamic.

Mark Addy, as a very different Hercules to the one you are used to, is the rough edge that completes this particular triangle. But, as the cast are keen to stress, Atlantis has been carefully designed to be more than just a boys’ show.

Sarah Parish and Jemima Rooper, if their interplay at the press call is anything to go by, are clearly having a hoot. The former is in her element bestowing putdowns and literal bitch slaps, while the latter, as an origin-story version of Medusa, we are told, will get to reveal her inner tomboy before she unleashes her inner witch.

To say much more than this would be to stray into spoiler territory. But the final word goes to Rooper who says of the programme, ‘There’s romance! There’s adventure! There’s dough! Baps! Floury baps!’

Sounds to us like that’s something for all the family, then.

Atlantis begins on Saturday 28 September on BBC One.

> Take a look at our report on our visit to the Atlantis set earlier this year.

Watch the Atlantis launch trailer…

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