If you find yourself walking down a residential street at the right time on a Saturday or Sunday evening, it's likely half of the television screens you glimpse through the windows will be tuned to one thing. That thing features matching sparkly outfits, sashaying duos, terrible autocue jokes from a National Treasure and a whole lot of flesh. The nation has gone mad for Strictly Come Dancing.
The BBC entertainment show has always been popular, but its current tenth season has experienced the highest ever ratings, with the programme in which Fern Britton was turfed off last month peaking at 11.4 million, trouncing its prime time X Factor rival. This means it was watched by almost half the viewing audience during the final five minutes, and added 400,000 viewers to its previous figures.
And it turns out this relish for the rumba, this craving for the cha cha cha, does not stop at watching the show or doing the dishes with its addictive theme tune stuck in your head. Dance schools in the Westcountry report a sustained surge in demand, with eager couples queuing up to replicate their favourite celebrity and professional partnerships.
Bob Tanner has been dancing for 60 years and runs classes all over the Plymouth area with his dance school, Tanner-J. The lively octogenarian says that after Strictly Come Dancing first aired in 2004 they saw a "terrific influx" in pupil numbers, with one class rising from five couples to 40. He said: "It was incredible, all the classes were full up. We started four new beginner classes in the weeks around that date and it hasn't slowed down since."
Bob and his team teach all ages, all sizes and a vast array of professions including surgeons, plumbers, accountants and bricklayers. His partner and fellow dance teacher Sally Dunn said it is often the men who discover a new passion, adding: "Most of the time it is the women who want to start and drag their other half along, but before you know it they're hooked and keener than the wives. They all seem to be fans of the show and lots tell us that's what gave them the idea to start."
The pair take pride in tackling even those who are sure they have two left feet, and I'm told by their pupils that Bob has "the patience of a saint" after decades of being trodden on by fledgling dancers.
I join the couple at their Friday evening Ballroom and Latin class at Saltash Guildhall. The atmosphere is relaxed and friendly, with around 18 couples warming up by practising the moves they learned last week to a jaunty soundtrack that could have come straight from Strictly.
Dean and Teresa Roberts, from Plymouth, have been coming since September. Teresa, a 45-year-old medical secretary, said: "We've been watching the show since the third series and I used to just wish I could dance like them."
Dean, a Commander in the Royal Navy based at Devonport, added: "I've always had an inner desire to stop dancing like a clown. There are also a lot of nice functions with my work so we're hoping to stun everybody with our new moves this month."
He said the physical demands had been surprising, adding: "They always talk about it on Strictly, but I had no idea. In the past I've been a keen footballer, rugby player and triathlete, but I'm using muscles I knew nothing about. I get a bit of stick about the dancing from my workmates but it's all banter and actually people are interested."
Pauline and Cliff Weiss, semi-retired accountants from Calstock, have been coming to Bob's lessons for nearly a year. Cliff told me: "It's good exercise, keeps the brain going and gives you a bit of self confidence. A lot of life is about sitting – at a desk or in your car – and this is a welcome change and a great social outlet."
After the warm up, the class divides into beginner and intermediate groups. My husband and I join the former, who are getting to grips with the waltz. The men are taken through the steps first whilst we ladies sit appraising them on the other side of the hall. Sally then dances with each of the men – who get an encouraging round of applause – before it is our turn.
Even this simplest of dances proves tricky for me. My other half, never afraid of embracing the flamboyant (he once took his mum to an Elton John concert) is irritatingly competent. At one stage he leans in – I think for a romantic comment – but murmurs "take smaller steps... you're not trying to lunge."
My ineptitude not withstanding, this is fun. Watching the couples glide around the room, there is also something very touching in the intimacy and intensity – the closeness and the concentration it requires. After a busy and stressful week, for this hour on a Friday night they have chosen to do something together.
Sandra Bell, a fraud officer with the NHS, tells me: "They say it is one of the best things you can do for a relationship. For this hour you get to hold on to him and he can't get away."
As well as the benefit for their business, Bob and Sally are self confessed Strictly addicts with deep rooted ties to the show. Bob has judged competitions alongside Len Goodman in the past and Sally and her sister once won a section of the original Come Dancing show in the 70s.
"We find ourselves wincing when they make mistakes," said Bob. "Mostly I think the judges are very good. Craig Revel Horwood is rude, but some people watch the programme because they love him and his comments. At the end of the day it is all about entertainment."
He said the format and skills of the dancers on the show can lead to high expectations from new pupils.
"They expect to pick it up as quickly as the celebrities," he said, "they want to go fast, get the shoes and the costumes and as soon as they've learnt something they want to know what's next. It's great, but you do have to start off basic and work from there."
Other dance schools in the Westcountry are also feeling the Strictly factor. The Charles Colman World of Dance, based in Camborne, said the real change has been a new male interest in taking to the floor. Teacher Angela Colman said: "When Darren Gough won Strictly in 2005 all the chaps suddenly thought it could be a manly thing to do, something actually quite athletic. The show has been good for us, everybody wants to come and learn like the stars, and at this time of year they also want something to do in the cold evenings. It has put dancing in a better light."
As Bob congratulates the class and we pack up our things, one lady and I watch her husband waltzing around the room alone. As he blissfully leads his imaginary partner, she confides: "He does this all the time, even in Tesco. I just pretend I'm not with him."
For more information visit http://tanner-j.co.uk or call 01752 283828. For the Charles Colman World of Dance call 01209 715541 or email firstname.lastname@example.org