So is this fabulous episode destined to be an all-time classic? It’s clever, fast, funny, eerie, surprising and tearjerking – all in one spectacularly polished package. And Steven Moffat steps over 49 years of Dalek baggage to make them fresh and menacing again.

Asylum of the Daleks ticks all my boxes as a Doctor Who fan of more than 40 years standing. I have crystal-clear memories of Day of the Daleks – the most enthralling thing on television in 1972 – as Jon Pertwee’s Doctor and his companion Jo Grant became immersed in a spooky, timey-wimey Dalek mystery.

And with my fan-boy hat firmly jammed on, I thought what a spooky, timey-wimey delight it would be to watch this latest episode at my house with Katy Manning, who played my childhood heroine Jo all those years ago.

I’m pressing her to play critic for RT, even though she warns, “I just get into the story. I’m not one of those who sits and analyses it. I’m right there in the moment and where it goes, I go.” The episode begins and she’s gripped from the off, leaning avidly towards the screen.

First up, the Big Secret. At the BFI premiere in August, I must admit it took me a moment to realise I was staring at the new companion Jenna-Louise Coleman. Five episodes early! As Moffat put it after the screening: “This room froze in a strange way when Jenna – who isn’t supposed to turn up till Christmas – turned up right in front of you.”

Katy identifies her at once. “She’s the girl that’s taking over, isn’t she? Is that the big surprise!?” she explodes. “I’ve got far better secrets than that, mate. Trust me.” She also ribs me for my slowness at the premiere. “It’s pretty fricking obvious it’s her. You don’t have to be a fan to know who that is. I got it straightaway. No problem at all. I’m on the money here!” she laughs.

Little else is said as Asylum of the Daleks rumbles on. Katy coos over their prime minister (a mutant in a jar): she loves all God’s creatures, the uglier, the better. When the Doctor, Amy and Rory tumble down a beam to the asylum, she says, “I’ve done a lot of that as Jo! Although I haven’t been fired at a planet, I probably fired at a planet.”

As the zombies come to life, Katy is thrilled: “Urgghh! Oohh! – loving it!” We both enjoy the “Eggs-ter-min-ate” business, first with Rory, then with soufflé girl Oswin. “Eggs. Oh God, that’s divine. I love pay-off. If anything that’s introduced isn’t paid off, I get minty. That’s why I love these new scripts.”

Towards the end we chuckle at the Daleks and the Doctor repeating “Doc-tor who..? Doc-tor who..?” as Moffat continues his mission to reinforce the mystery at the heart of the programme – “putting the ‘who’ back into Doctor Who” as he promised last year.

Katy emits a throaty cackle as Amy catches Rory doing his little “Yes!” on their doorstep. And then with the final shot of the Doctor inside the Tardis, she’s delighted to recall, “I did go in there...” (in 2010, alongside Elisabeth Sladen and Matt Smith in The Sarah Jane Adventures).

The episode ends and Katy sits back, composing her thoughts. “That was absolutely stunning. I’ve got to tell you this: when I’m watching Doctor Who, I forget I’ve ever been in it. It doesn’t even cross my mind. Because it’s a very different show, so grown-up now. I think Steven Moffat is exactly right with what he’s done. It’s progressed exactly the way it should.”

She made two Dalek serials in the 1970s and appreciates how they’ve developed. First with the 2005 episode simply titled Dalek, written by Robert Shearman: “He’s my hero. And what Steven’s done is taken the Daleks further without falling into the trap of using Davros. The moment I saw Davros in the 70s, looking like everybody on the Tube round about six o’clock at night with their headphones on, it took away the menace of something that isn’t human. Because suddenly it’s half a bloke in there. There’s nothing human about a Dalek.”

But, I argue, Moffat has blended the human and the Dalek so cleverly here, reusing his idea of nanogene transformation from his 2005 two-parter, The Empty Child/The Doctor Dances (“Are you my mummy?”). He’s even made the new companion a Dalek! 

What does Katy make of Oswin? “I’m going to like her.” But Oswin Oswald… Didn’t everyone predict her name would be Clara? And how come she’s a bloomin’ Dalek!? “I don’t know about the full Dalek conversion. Look, this is sci-fi. We can de-convert!”

Yet surely this is where Oswin/Clara’s story will end, Dalek-ised and memory-wiped...? I like her final, telling line: “Run, you clever boy. And remember.” Or perhaps it'll transpire she's a looky-likey, cousins like Freema Agyeman played when she started... “I don’t know where it’s going and don’t want to guess,” says Katy, “but obviously if she’s going to be the new girl, we’re going to have x number of stories with her. Maybe they don’t know where it’s going to go. How often do you start a story like that?”

That mirrors River Song, I point out, another woman of mystery killed off in her debut story whose earlier life is coloured in later. “Yes, I was confused with River Song,” admits Katy. “I don’t think I was alone there. Truthfully, that character slightly jarred for me. I don’t know why, because I think Alex Kingston’s a fabulous actress.”

She’s effusive about the three leads. “Matt’s one of my most favourite young actors. Without a shadow of doubt, I love what he does. Amy has been a wonderful companion. I love the way Karen Gillan performs the character. She gives me all the levels I actually want. She can scream, she can be tough, she can be brave, cynical… She’s all those things that work beautifully with this younger Doctor.” Katy’s also met Arthur Darvill, “briefly at a signing – rolling a cigarette somewhere. It’s how you meet in my business. He’s a cool dude. A smashing actor.”

As for the episode: “It has a quirky Alice in Wonderland quality – going from the Daleks up there in this huge sort of Albert Hall of Daleks, spiralling down, down into the hole where Rory sees all the old Daleks… What’s glorious for me is to see so many Daleks that aren’t tiny little cardboard things superimposed on the screen.” 

Final word of praise for director Nick Hurran. “He should be congratulated,” she says. “It was beautifully directed, beautifully lit. It was shot every bit as well as an action movie – you can well-quote me on that! It was as good as anything I see that people spend zillions of dollars on. 

“D’you know what? I would love to have been in it now,” she confides. “Not as an old person, not an old Katy...” the husky voice breaks “…but as a young Katy. I would love to have been a young person in Doctor Who now.”