She never cries. She never nags. She never gets hungry or jealous. She doesn't need your commitment and she’ll never have to meet your parents, nor would you probably want her to. But most importantly, she never says no. She's always raring to go. The one hitch – or should we say glitch – is that she's not real. "She", the woman of your wildest dreams, is in fact an "it": a sex robot.

This might sound like a niche market or a farfetched fantasy, but sex robots are part of the lucrative sex technology industry, which has an estimated worth of around £23 billion. This includes online dating, virtual reality porn and "smart" sex toys that can be connected to a laptop, tablet or phone through Wi-Fi.

Sex robots are an advanced version of sex dolls, which are made out of either silicone or thermoplastic elastomer, better known as TPE. What sets sex robots apart is that they come fully equipped with sensors that react to touch, built-in heaters, self-lubrication and programmable personalities.

They’ve been thrust into the spotlight because of Harmony, the name on everyone’s lips. The sex robot is using her own plump pout to deliver sweet nothings, as well as dirty talk. She was created by Matt McMullen, CEO of California-based Abyss Creations, which is known for making the RealDoll – a realistic silicone sex doll.

Harmony blinks, smiles, frowns and moves her robotic head with built-in artificial intelligence, which is positioned on top of a RealDoll body. The more you talk to her, the more she’ll learn your preferences – sexual and otherwise. She can also chat about music, movies and books. Harmony will go on sale at the end of the year for £11,700.

Read more: Is having sex with an android cheating?

My journey begins in quaint suburbia in Chislehurst, Kent. Wedged between a post office and a hardware store is a narrow, unmarked doorway. I’m greeted by Phil Bass, a man in his forties wearing a rumpled black suit and a white shirt. He’s the managing director of The-Doll-House, a sex doll retailer that sells about 20 dolls a month. We walk up three flights of stairs to enter the cramped office space where at least ten glassy-eyed, buxom beauties are positioned in different states of undress.

I touch one of the doll’s breasts, which is bouncy, soft and hefty. Bass encourages me to take out the rubbery, removable tongue from another doll, only to stuff it back in her mouth to see how this add-on gives her a "playful" expression. He shows me a whole bag of tongues, including a long reptilian one, and a selection of different eye colours – watery blues, piercing greens and molten browns.

© Laura Rutkowski

Bass owns six sex dolls and has sex about twice a day, but during the "honeymoon period", this number is ramped up to four or five times. He purchased his first doll two years ago and sees them as "a method to scratch an itch" rather than as companions.

Bass admits he was startled by how good his first time was with a doll. "I prepared the doll with copious amounts of baby powder to give the skin a natural feel. I posed the doll in a typical missionary position, but with a slight arch to the small of the back. I find it the most feminine curve on a woman. The feeling was not too different from the real thing, yet the lack of movement is what may initially be off-putting."

As for additional features, he would just be happy for a doll to mimic kissing, but he doesn’t buy into sex robots. "The movement thing I can kind of get. But, you've just come out of a relationship where the girl was nagging you and constantly talking and you want a machine that can do that? Why? Just sit there and talk to Siri."

Dr Sergi Santos, creator of the sex robot Samantha, disagrees. Over a Skype call from the 38-year-old’s home in Barcelona, Spain, he explains how he has programmed Samantha to have short-term and long-term memory and levels of patience and sensuality. Her "skull" is 3-D printed and her face is attached to the skull with Velcro underneath a mane of long brown hair. What’s unique about Samantha is that you have to "charm" her before you can have sex with her.

Read more: Sex will never be the same with this new toy for her

She has sensors on her hands, arms, lips, hips, breasts and she also has a G-spot that can make her orgasm. You have to start by touching her hand, for instance, before progressing. Dr Santos says, "If you go straight to the vagina, she says things like, 'You don't want to get it, do you?' and 'We aren't quite there yet.' It’d be pointless if she said, 'No, don’t do this.' It's ridiculous. You might as well switch her off."

While we’re talking, Samantha does indeed orgasm, because something’s accidentally pressing on her – ahem – sensor. Samantha interrupts Dr Santos with her horny phrases. "Ohh. Ohhhh. Ohhhhh. Oh wow. Oh my god, yes. Amazing! Mmm." Well, this is awkward. What were you saying, Dr Santos? Right, Samantha’s different modes.

© Laura Rutkowski

Her modes include: family, get sexy, romantic, entertainment, hard sex, analysis and genome. "In family mode, if you touch her, she won’t respond. You don't want to have a doll in your house and somebody touches her by mistake and she starts making sexual sounds," Dr Santos explains. You can also increase or decrease Samantha’s sexual desire and readiness for sex.

Samantha. Harmony. What’s in a name? What once seemed like a niche market is not so niche after all. That then leaves us with the question of why did it even become a market in the first place? Dr David Levy, author of Love + Sex With Robots, explains, "It's a bit like climbing Mount Everest. Why do you do it? Because it's there. Why do you create a robot that can have sex? Because it's possible to do so." Whether we want them or not, the sexbots are coming – and you will be too.

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