The smooching comes with some thrills, as Smithy faces his toughest challenge to date when he goes undercover in an operation to expose a gun-running racket. Stevie accidentally becomes his undercover girlfriend – and finds she quite likes it! – while viewers will question if Smithy, taken hostage at gunpoint, has got what it takes to keep his nerve.

So, is there a rose-coloured future for our unlikely twosome? ‘There’s definitely a fair bit of sexual tension,’ says 33-year-old Alex, who reckons this is Smithy’s most exciting case to date. Meanwhile Lucy, who of course sprang to fame as EastEnders’ ever-suffering Natalie, is having the time of her life playing the street-savvy Stevie.

‘It’s hilarious, because Stevie really fancies him as his undercover alter ego – but not when he’s Smithy!’ laughs Lucy, 31.

We Bill addicts at OK! needed some answers  so we decided to give our guests a good grilling with the promise of a fabulous lunch at the Michelin-starred Indian restaurant Quilon, just a crown’s throw from Buckingham Palace, where executive chef Sriram Aylur’s outstanding dishes equalled the spiciness of the insider gossip…

Lucy, how does life on The Bill compare with EastEnders?

It’s lovely playing cops and robbers. I’ve appeared in The Bill three times in the past as a guest and I always thought, what a nice bunch of people! So I jumped at the chance to be a regular character. And I love playing Stevie. In some ways, she’s an extension of Natalie, my EastEnders character, but she’s less of a pushover.

How did you two become the latest canoodling coppers on the show?
Alex: It’s complicated! This new four-part story sees Smithy go undercover and infiltrate a gang that is buying handguns to sell to gangs. He’s posing as an armourer, and he’s on the phone to one of the lads in the gang when Stevie comes in, mouthing off, so Smithy has to cover – and the first thing that comes into his head is ‘girlfriend’! They become boyfriend and girlfriend for the undercover role.

So is there some true romance, or is it just a bit of make believe?
Alex: I’d say there’s quite a bit of sexual tension! You’ve got to keep up the undercover pretence so there might be a bit of kissing and cuddling going on!
Lucy: The funny thing is that Stevie fancies him as his undercover alter ego – but not as Smithy! So while there’s a bit of chemistry going on, as far as Stevie’s concerned, Smithy has to pretend to be this tough gunsmith, so he’s a bit confused where she’s coming from!

Doesn’t your height difference make things a bit awkward?
Alex: Yeah, I’m 6ft, and Lucy’s 2ft 9in!
Lucy: I think you’ll find I’m 5ft tall. We’ve tried to make sure that Alex is either stooping or leaning against something for a lot of scenes!

Lucy, isn’t Smithy a better catch for you than Barry in EastEnders?
Lucy: I won’t have a word said against the lovely Shaun Williamson, who played Barry! I see Shaun and his wife regularly, we’re all really great mates.

Who else among your former EastEnders colleagues do you keep up with?
I speak to Sid Owen [who plays Ricky Butcher] every now and then, I’ve spoken to Patsy Palmer [Bianca], and I speak to Charlie Brooks [who played Janine] all the time.

Alex, apart from the romance, this is a nail-biting storyline for Smithy, isn’t it?
Yes, Smithy gets taken off in a car at gunpoint, by a violent arms dealer called Kieran – played by former Coronation Street actor Rupert Hill – and he has to prove himself. He’s then given a gun in the car, blindfolded, and instructed to take it apart and reassemble it. So there’s poor old Smithy, with a gun to his head, thinking quite possibly that they’re going to shoot him.

How did you feel handling a gun?
I didn’t mind it, but guns are scary. I went on a special course where we did some blank firing, as I have to fire guns in the episode, so they wanted to make sure I was comfortable handling the weapons. I found it quite hard sometimes to pull the trigger, just because of thinking what you’re actually doing. It feels very alien and weird. At the same time, boys will be boys, and you’re loving the cops and robbers element, so it’s very exciting too.

Lucy, you were very young when you joined EastEnders, and then you left the show for a while. Was it very different coming back the second time – did you feel you’d grown up a lot?
I was ready to go back, yes. Going into EastEnders the first time I was obviously excited, but I was just 17 and totally unprepared for the level of press interest and public interest. Some of the kids going into it were fantastic, and I was in awe of them. I was just so embarrassed, wondering why everybody was looking at me. When I went back, I was at ease with it all, and ready to embrace the experience properly, so the second time was better for me.

Is the door open for you to go back?
You can never say never. At the moment, I love Stevie in The Bill so much, and I’m totally happy staying there. I feel Natalie’s had her day and she got wrung dry. She would have to have a massive turnaround; she had a big turnaround anyway. So you have to learn to walk away. I love the fact that Ricky and Bianca are in there again, they’ve got the natural storyline. But you never know!

Alex, are you like Smithy at all?
He’s a very loyal soldier to the police force, he’s a 24-hours-a-day copper and I’d like to think I’m a loyal person, especially with my family – my fiancée Sarah, who I met when she was a make-up artist on The Bill, and our children Flora, who’s nearly five, and Jack, who’s 20 months old. I appreciate that side of my life more than ever. It’s all about those people who give you kisses and cuddles and make you feel the best thing in the whole world.

Could you two ever be cops in real life?
Alex: If it meant driving around, mucking about in the canteen, not having to get involved in any fights, and not having to do any paperwork, then probably – so no! And it’s just getting more and more dangerous. I’m quite happy doing it for fun. If someone pulls a knife out on me, I’m guessing it’s rubber.

Lucy: It’s quite good fun on The Bill, but I don’t know if I’ve got any insight what it’s like to be a cop. We don’t have to do the paperwork, we don’t have the shift work, and we don’t actually have to arrest someone. And I’m sure in real life the criminals wouldn’t be throwing themselves onto the floor for me, to make me look stronger than I am!

Lucy, did you take any mementoes from your time on EastEnders?
I took my name plate off my dressing room door. It says Lucy Speed – London Borough of Walford. I took a load of Lucy Benjamin’s shoes as well! The whole budget was spent on Lucy’s shoes. I used to buy them really cheaply, and I ended up buying up Lucy’s entire shoe wardrobe!

Alex, you won The Weakest Link – how amazing was that?
I was stunned. I had no idea how it happened, it was absolutely bizarre. I was horrible, though – I voted off John Altman just to get Trudie Goodwin [The Bill’s June Ackland] into the final. How could you vote off Trudie Goodwin? It was a goodies and baddies episode and I think we were there for the goodies! The three of us were left, and Trudie was the worst link in the round, but I couldn’t vote her off, so I voted John off, and it was me and Trudie in the final.

What was Anne Robinson like?
She was really scary. She flirted with me a bit. She told me she fancied me. The floor manager told me: ‘If she starts flirting with you, flirt back.’ I think I got a bit carried away – some of my banter was edited out! But I was so proud – I raised £9,450 for Kids In Need, an Essex-based charity that grants wishes for sick and terminally ill children.

Would you do any other TV shows, maybe a reality show?
Alex: I don’t think so. I couldn’t do anything like Celebrity Big Brother. What’s the point of that? Just having people watching you sitting around on the sofa.
Lucy: I was asked to go on the first Strictly Come Dancing and I said no – and I’m gutted really, because I’d quite like to do it, having seen it now. I said no because I just wasn’t into reality TV, and I had no idea what it would be like, but now that’s the one that everyone wants to do! I couldn’t do Celebrity Big Brother – I’d kill my own career, because my gob is completely uncontrollable!

SEE THE DELICIOUS RECIPES FROM THEIR SPICY LUNCH AT QUILON...

‘THE BILL – GUN RUNNER’ IS ON ITV1 ON JULY 2 and 3 AT 8pm.
VISIT THE SHOW’S OFFICIAL WEBSITE AT WWW.THEBILL.COM

QUILON, 41 BUCKINGHAM GATE, LONDON SW1E 6AF.
TEL 020 7821 1899 OR VISIT WWW.THEQUILONRESTAURANT.COM.