Queen of shops goes undercover to name and shame

To her, store layout is an exact science, window dressing a serious art and incorrect pricing a cardinal sin. While the gravity with which she approaches the High Street may pass the rest of us by, her latest target is likely to strike a chord – customer service or rather Britain's lack of it.

"The so-called service industry has become a faceless, 'I couldn't give a monkey's' business'," she says, gesticulating wildly. "I think we're one of the worst countries in the world for customer service now. Look at (Tesco] Metro supermarkets. Nobody even says 'Hello', it's just beep, beep, 'Have you got a Clubcard?' They don't even give you the price, you've got to look at the machine. It's just tragic. It's like we've lost all type of communication or any care for it."

Portas is not alone in feeling frustrated with "the fat cat companies making a serious amount of money but not offering a voice to the consumer", but she probably has a better chance than most in getting them to change their ways. The 50-year-old has spent her entire career working in retail, beginning as a Saturday girl in John Lewis and eventually being credited with transforming Harvey Nichols into a household name. By 1997 she had set up her own brand communication agency, Yellowdoor, which has helped the likes of Waitrose, Clarks, Oasis, Clinique and Louis Vuitton.

"When retail is done right, a day at the shops is one of the most exiting and fun things to do, but a bad experience can really pull your day down," she says, her disdain not solely reserved for shops. "I once said to this waiter, 'Can you talk me through the wine list?' and he said, 'Your guess is as good as mine'."

Having taken on independent shops and the charity sector, for her latest series the instantly recognisable Portas attempts to go undercover talking to shoppers before trying to take complaints to the top. Faced with large companies boasting slick PR machines, some amount of resistance was inevitable.

"That's what makes good TV," she says. "They go, 'We look after the customer', and then you show them undercover footage. Then they say, 'We trained them' and you find out the training is a notice on the back of the door that says: 'Smile before you go on stage'. You have to wonder why they aren't giving their staff passion, training and time. Why aren't they making people feel like this is a career?"

Portas has two teenagers from her previous marriage to Unilever executive Graham (she has since come out as gay and married Grazia magazine's fashion editor- at-large Melanie Rickey in 2010) and, just as she has instilled in them that they deserve nothing less than the best service, so she's determined to do the same for the Great British public. And if it's not happening, she says, we must learn to complain.

"We are a bit apathetic when it comes to bad service, but vote with your feet and just don't turn up," says Portas, who is also planning to set up an online forum for complaints. "People moan about the internet, but for a voice of the people it's amazing. I love the fact at the click of a button people can let the world know about their shopping experience.

"I don't want a country of angry people, but I want people to feel they can really say, 'I'm not being looked after' and some of these brands can be shamed."

The biggest offender for Portas is the rise of high street fashion stores which have adopted the stack 'em high, sell 'em cheap philosophy from discount supermarkets.

"One of the days I was filming, I went into one of the fast fashion stores and there were clothes on the floor. The sales team were huffing and piling it back up, there were 40 in one queue, 45 in another and people were just putting up with it. My 14-year-old was going 'Are they mad?' And you think, 'Probably'.

"Then I looked at the staff. They were like, 'Only four garments, only four garments'. I mean, why would they be motivated? The customers were hating it, the staff were hating it and you've got this bloke in head office who thinks it's all alright because he's making profits. We've ended up with sales teams just stocking shop floors instead of any type of service – I think that's criminal."

There she goes again. Portas may be occasionally guilty of overstating her case, but when it comes to shopping she's a woman who undeniably knows her stuff.

Mary Portas: Secret Shopper begins on Channel 4 on Wednesday, January 19.