It was enough to make any of the Made In Chelsea set cry into their champagne, when E4 reality series favourite Alexandra 'Binky' Felstead realised her caddish beau Alex Mytton had been unfaithful - but claimed he couldn't actually remember anything about the illicit encounter because he was so drunk.

Poor Binky sobbed her heart out on screen before decamping to New York (as you do) to think things over, then returning to Chelsea willing to forgive and start again, only to be faced with a sobering speech from a doe-eyed Alex saying he couldn't face hurting her again. Which she took to mean he was dumping her. Or was he?

Of course, non-fans of MIC - and similar reality shows like Towie and Geordie Shore - might say, 'Who cares?' But it would seem quite a lot of people do, judging by Binky's 673,000 Twitter followers alone. The Bafta-winning series gained 866,000 viewers in the opening episode of the seventh series in April and has maintained that figure with each episode (a 5.1% share of the 10-11pm TV audience).

"What you're seeing now happened six weeks ago. All I can basically say is that it's been terribly tough," says Binky now. "When trust has gone in a relationship, it's very hard to get it back again and I trusted him 100%. It was heartbreaking to find out I trusted someone who lied to me the whole time."

Indeed, MIC has not only fuelled Binky's profile enough to help her become a beauty blogger, she's also launched her own clothing line and nail varnish range, as well as becoming the face of Rimmel Sun Shimmer.

Now, at the tender age of 23, she has also written her autobiography, Being Binky: My Life In Chelsea, which gives us a slightly bigger glimpse of her life before the champagne corks started popping on TV.

The book covers her privileged upbringing in the East Sussex countryside, the boarding schools, pony clubs, luxury ski holidays, and the food fights relished by all at the Christmas table. Along with her own tips on such necessities as 'Need-to-know Chelsea Facts', 'Top Etiquette Essentials' and 'Top Red Carpet Posing Tips'. The sort of advice we all need...

Today, she arrives fashionably late to our interview at a stylish hotel, dressed down in skinny jeans, a voluminous black jumper and wedged trainers - but she has that air of class and cut glass accent that only an expensive upbringing can buy.

For all my preconceptions, I like Binky. She talks quickly, a little nervously, about her relationship with Alex, although her manager, who sits in on the interview, is quick to stem any line of questioning he doesn't like. Only a few questions about Alex, please. And no, I'm told curtly, we're not going down the road of whether anyone else was involved in her parents' divorce.

She says of Alex, her voice faltering: "I think he felt, 'Do I actually need or want to be in a relationship?' It was all very quick for him. When you love someone, it's not easy to turn it off. But I'm feeling strong, I've got lovely support from friends, family and fans." At which point her manager wants us to move on.

Of course, she and her MIC pals Spencer, Cheska, Robbo, Jamie, Lucy et al, have endured their share of criticism since the first series launched in 2011, with critics branding them 'gilded socialites', 'spray-tanned exhibitionists' and 'privately educated hedonistic' youngsters, but Binky says she is certainly not one of those.

"I wanted to point out to the public that the perception of us all being posh brats is absolutely wrong. I've had a lovely upbringing, agreed, but I'm very grateful for everything I've had. I believe I'm a grounded person and enjoy working and making my own money. I can do what I want with it.

"I love going out and partying, although I'm trying to cut down now. But it's basically about a bunch of 23-year-olds going out and having fun with their friends. It's no different to anyone else doing that, it's just that we go to different locations. I've always worked for my money. I feel lucky, I'm not arrogant with it."

Before she became one of the MIC lovelies, Binky was a receptionist/secretary, and her earnings didn't cover her champagne lifestyle. "But I had a lot of friends who did have a nice lifestyle who looked after me. When I went to work in London, all my friends were at university but my brother [Ollie, who's nine years older] and his friends could afford [the Chelsea lifestyle] because they worked in the city, and they'd look after me."

She insists that MIC is not scripted or fake, although the cameras obviously have to know where the Chelsea friends will be at any one time, so they can set up for shoots. And situations are put under the magnifying glass, so romances move quicker than they would in ordinary life.

Does it bother her having her personal life, and particularly the boyfriend troubles, flaunted on the show?

"That's what I don't like, but that's what I've signed up for so I guess I have to go with it," she says, shrugging. "It was quite destroying to see myself break down. I didn't realise what I looked like. I was in tears watching it back. But cheating is not OK. I want girls to watch it and think, actually that's what happens, but it's not OK."

Her mother, Jane Felstead, known on Twitter as Mummy Felstead, has also achieved celebrity status on the show, comforting her daughter and giving her pals sound advice, so much so that it has led to her becoming an agony aunt for the MailOnline.

Her father, Roger, had an information software business and travelled extensively while her mother was the 'perfect corporate wife', Binky recalls of her early years.

The youngest of three, she reveals that from an early age, her parents didn't seem particularly happy together. There was a lot of arguing and periods of stony silence. When her father changed career and bought a pub in East Sussex, their marriage broke down.

Binky admits that her own relationship with her father was difficult, partly because she felt so protective of her mother, who eventually moved to Brighton with her to start a new life.

The divorce, coupled with the bullying she suffered at school, resulted in Binky seeing a counsellor for a few months.

"It's not been easy," she says now. "I don't think I really appreciated what I had before I lost everything - we lost the big family house, my parents were fighting constantly, I was being bullied at school - but it's made me a stronger person. Counselling helped, but so did writing the book. It was like a big therapy session."

She didn't speak to her father for a year after the split, but he is now suffering from terminal cancer which has changed Binky's perception.

"He became a nicer person. You want to be able to make everything up again. Families are important. I like having my daddy back," she says. "I've been to a few chemo sessions with him. It isn't nice. I didn't really know him before but now I'm getting to know him a lot better.

"Hopefully one day they [my parents] will be reconciled. We'd like them to. They both love each other in a bizarre sort of way."

:: Being Binky by Binky Felstead is published by Simon & Schuster, priced £12.99. Available now